Here are a few I have found useful.

Pivots - I combined standard, mid, fib and cam in a single indicator as an early project to learn MT4 on build 187.

The Cam historical versions I coded after reading about how to trade cam pivots.

I have not looked at these in a few years and hope to get back to trading these.

On GBPUSD and EURUSD 15 minute they have worked great in the past few weeks.

The rules I remember:

If price goes long first wait for return to Green and go short with target at Red.

If price goes short first wait for return to Red and go long with target at Green.