For me, Google video search, Google books (Internet Archive is good, but doesn’t always have the same stuff), Adobe InDesign (but in the process of learning LaTeX), and Typewise. As for the Google stuff, I liked Whoogle a lot, but almost all their instances seem to have been blocked or shut down. Also, apologies if this is repeating an earlier post.
There are a bunch. There are fewer that are multiuser. Search alternativeto. Thing is people want more then double entry accounting. Electronic payment processing, reporting, payroll, AR, tax… Then how does it work with the professionals you hire.
Edit: For personal stuff, my wife and I use GNUCash. It does have small company features. I do not think it is concurrent though, but it can be used with an SQL backend though. We do not use the database mode so no experience with it.