Web Based Tools
The one and only tool that everyone should know. If you don't know it, start learning it. It is just the baseline of everything.
Is actually 8 tools - Best practices analyzer, Org Compare tool, Data Compare tool, Schema Lister, Field Creator and validation/trigger switcher
Profile Power Tools - Mass edit profiles
Literally does what it tells you. Allows you to mass edit profiles.
Google for salesforce - Search the web and only get Salesforce related results
Avoids you having to applya gazillion filters when doing your Google searches.
Json 2 apex - Create Apex based on your jason
Cert Score Calculator
Event Log Viewer
If you use Lucidchart to genarate your Entity Diagrams you should switch over to this. When you're done with LucidChart, what you have is an image.That work is lost. If you use DbDiagram or equivalent, you just write JSON, which you then can reuse to actually create your fields etc.
Doing SOQL queries that can be comre complex than reports, but without the hassle, since... a few years now ? no idea.