BleachBit (I'm currently trying it. Impressed so far.)

[rcjordan]

Very granular CClean on steroids.

Clean Your System and Free Disk Space
https://www.bleachbit.org/

[ergophobe]

I don't use these cleaners much anymore, but after a long time using CClean, I switched to Glary Utilities. It's worked well enough for years, but in my experience, they don't make any noticeable improvement.

Not like in the old days when you would clean the registry and defrag the disk and things would noticeable speed up.