Daniel Ferry covers mostly advanced Excel topics on his site, ExcelHero.com. He's a professional developer with over 25 years experience and has been using Excel since the earlier 1990s. If you're an intermediate to advanced Excel user, and interested in more advanced topics, check out his blog (not updated so far in 2014), which contains some very interesting in-depth articles. Some good examples include The Venerable SUMPRODUCT, The Imposing INDEX, and I Heart IF. Daniel's approach is more abstract, but leads to sophisticated and powerful solutions.
Rick Grantham is a process improvement consultant who focuses on Excel. He runs an interesting website called Spreadsheet Champion (http://rickgrantham.com) and he hosts ExcelTV, a Google Hangouts show that features Excel experts (authors, blog owners, consultants) talking about a wide variety of Excel topics. ExcelTV may be the most quirky and interesting thing going on in the Excel community right now. Check it out. Also, Rick has great Excel resource page on his website and a giant list of Excel books.
Mike Girvin is known online by the name ExcelIsFun. On on his Youtube channel he has an astonishing collection of over 2200 videos on Excel, organized in over 50 playlists. Mike has an almost encyclopedic understanding of Excel and is an extremely enthusiastic teacher, which you'll immediately notice in any of his videos. He has also published 2 books on Excel and several DVDs.
Ken Puls is a Certified Management Accountant (CPA, CMA) in Canada, and works as the Controller for a resort on Vancouver Island. In the Excel world, Ken is the Chief Training Officer at Excelguru.ca. Excelguru is a large Excel website that features a diverse forum, and a knowledge base with a variety of Excel tips, downloads, courses, and other Excel resources. Ken also maintains a blog with detailed posts on Excel, as well as other tools like Power Query and Power Pivot.
Mynda Treacy is co-founder of the online training site MyOnlineTrainingHub.com, which she manages together with her husband, Phil. The site contains an active blog, which is predominantly focused on tutorials for Excel. Many of the tutorials are very detailed and include video. MyOnlineTrainingHub also provides paid video training courses, but a good deal of content on the site is free. One of the courses developed by Mynda is a thorough and well-received course on Excel dashboards.
Felienne Hermans is doing some of the most interesting work related to Excel that we know of. She wrote an entire dissertation on spreadsheets, she runs a huge Excel MOOC (massive open online course), and she's analyzed and open-sourced all spreadsheets from Enron. She's done some very interesting research on how many spreadsheets companies use (it's a HUGE number), how long spreadsheets live, and what kind of spreadsheet errors typically occur. Did you know that 95% of US companies still use spreadsheets for financial reporting? Yep. For a great primer, see this video.
Rob Collie is an expert on PowerPivot, a free extension to Excel 2010 and 2013 that lets you mashup and analyze huge sets of disparate data without using complicated VLOOKUPS. He was one of the founding engineers behind PowerPivot while at Microsoft, and has authored two popular books on the subject. Rob also runs PowerpivotPro, a website that provides great information about PowerPivot and Excel. For a quick intro to PowerPivot, see Temperature Mashup Example and What is PowerPivot.
Ron de Bruin is an Excel developer who works with both Mac and Windows versions of Excel. He runs the wonderfully spartan website rondebruin.nl. On his site, you can find both Windows and Mac tips, which are focused on VBA solutions to a variety of business problems. You can also find the Excel Function Bible, and articles Ron has written for MSDN and other publications.
His full name is Purna Duggirala, but he is known online by his nickname, Chandoo. Together with a small team, he runs a very busy Excel site at chandoo.org. Chandoo started chandoo.org in 2004 and shifted focus to Microsoft Excel in 2007. Notable sections include advanced Excel skills, formulas, dashboards, and VBA. Chandoo.org also hosts an active forum with over 100,000 messages. Chandoo has a knack for combining technical know-how with a wonderfully warm and human perspective.
Chris Newman (a.k.a. Chris Macro) is a financial analyst who runs the website www.thespreadsheetguru.com, which is focused on smart ways to analyze data in Excel, particularly with VBA. The Spreadsheet Guru is visually unique, and contains many helpful sections, including tools and utilities, a code vault with many full-blown VBA snippets, and detailed tutorials. As Chris says on his site, Spreadsheet Gurus are always asking the question, "Is there a better, faster, more accurate way to do this?" We couldn't say it better ourselves!
Debra Dalgleish is an independent computer consultant who specializes in Microsoft Excel and Access development. Debra runs the website Contextures, which features a wide-ranging collection of quality Excel information. In addition to an active blog, Contextures has a great list of Excel tips (over 300), a list of videos, and a very substantial download page. Debra is also a Pivot Table expert and has authored three books on Excel Pivot Tables. She also provides in-depth information on conditional formatting, data validation, and autofilters.
Jon Wittwer runs the website vertex42.com, a site specializing in high quality templates, calculators, calendars, schedules, and other tools designed to educate and increase productivity. Vertex42 hosts a huge variety of Excel templates, including calendars, invoice templates, mortgage calculators, grade books, financial statements, todo lists — even wedding and meal planners! In addition, Jon has written some interesting articles on Excel, and maintains a blog. Not to miss: a great list of over 100 Excel tips.
Bill Jelen is a true luminary in the Excel world. He's been doing Excel consulting since 1998, and has written more than 40 books on Excel. His main website, MrExcel.com, is one of the largest Excel sites, and the forum section is arguably the best Excel forum on the planet, with millions of posts, and a large collection of very sharp Excel experts and enthusiasts. Bill also maintains an active channel of short podcasts on Youtube.
Ann K. Emery an independent consultant who specializes in data visualization and data analysis. She runs an active blog at http://annkemery.com and writes frequently about Excel. With a background in Evaluation, Ann focuses on the Excel skills needed to collect, analyze, and present data, and many of her articles include how-to videos with great real-world examples. The Excel information on her website is organized in a master index, and sample topics include: importing and merging data sets, cleaning and recoding, pivot tables, and charts. Ann is a good example of a professional using Excel in a specific context.
Zack Barresse runs the websites exceltables.com and vbaexpress.com. Zack is an Excel MVP and a full time consultant working with Excel and Access. He's recently written a book on the subject and is currently finishing up a Table Tools add-in, which will be available in both a free and a pro version available (exceltables.com/add-in/). Zack also has deep experience with Excel templates, and worked with Microsoft to build templates for Excel 2013, Excel Online and Excel for iPad.
Bob Umlas is the longest running Excel MVP. He has been working with Excel since version 0.99, and has received the Excel MVP award for more than 20 years, since the inception of the program in 1995! Bob is a prolific contributor to the AllExperts site (bio and recent posts here) and a frequent speaker at Excel User Conference meetings. He is also the author ofExcel Outside the Box, This Isn't Excel, It's Magic, and more than 300 articles on all aspects of Excel (examples here). In addition, Bob is the technical editor of Bill Jelen's Excel books.
John Walkenbach is a prolific and bestselling Microsoft Excel author. He has written over 50 books about Excel, including books on VBA, formulas, and the bestselling Excel Bible series. John also runs the website spreadsheetpage.com, one of the longest running Excel sites around (est. 1996). His website has tips, books, a categorized list of Excel resources, and a blog. John has a clear and direct writing style, and an excellent sense of humor.
Allen Wyatt is the Excel expert behind two large Excel sites: excel.tips.net, and excelribbon.tips.net. Excel.tips.net provides tips for Excel 97-2003, and excelribbon.tips.net covers Excel 2007-2016. Allen has been publishing his ExcelTips newsletter every week since November 1998. As of early 2016, he has more than 3000 Excel tips on both sites together. The tips themselves cover a wide range of topics, including formulas, macros, formatting, graphics, data validation, and many other categories. Allen has been working in the computer and publishing industries for more than two decades, and has published more than 50 non-fiction books.
Jan Karel is an long time Excel MVP who develops custom solutions focused on Microsoft Office, with deep expertise in Excel and VBA. He runs the website www.jkp-ads.com, where you can find an interesting collection of articles, training events, and utilities. For a good overview of topics, see this list of in-depth articles. Jan develops some cool and useful utilities for Excel, including NameManager, RefTreeAnalyser, and Flexfind. You can find a full list on the downloads page.