What features do you use often And what features are not that useful in an IDE and can be considered bloat?

Being able to build projects and debug them is a given. Why would anyone use an IDE that did not supported building or running a project?

Developers spend most/practically all their time navigating through a project. Therefore, features such as opening files, searching for symbols, going to definitions, navigating back to points you were in, end up being the ones everyone uses the most. Also, code bookmarks are also of critical importance to work on specific tasks.

Support for refactoring primitives is also of critical importance. It's extremely convenient to extract/inline functions, rename symbols across the whole project, automatically generate code such as classes and their unit tests, etc. Nowadays, if an IDE does not support basic refactoring features such as extract/inline function/variable then I'd argue that it's not worth bothering with.

Finally, source code formatting. It's surprising the impact on team dynamics and productivity that we get by having an entire team on the same page with regards to where a space is expected to show and not show up.

I'm sure that there are plenty of spectacular features that should be must-haves but I'm oblivious to. Not using them doesn't mean they are bloat.