Russian twist, Crunches, hanging leg raises
If you get bored, there are plenty of variations.
If you find it's too easy, introduce free weights or medicine balls.
Standing weight lifting exercises also use the core, e.g. squats, dumbbell exercises
I need some good core exercises help please preferably gym related ones please and thank you
Depends how fancy you want to get but all you really need are decline situps for upper abs (you can add a twist to it for oblique work) and leg raises for lower abs. Both of these can be weighted to adjust for difficulty.