I stick with few basic exercises:

- kettlebell exercises work my entire core and posterior chain
- front squats and standing overhead press with a barbell or kettlebells
- various TRX exercises are great for strengthening your core
- push ups and pull ups also hit your core besides being great for upper body
- hanging leg raises are great
- L-Sit on parallel bars

Core training has become a circus act at a lot of gyms and people do all kinds of ridiculous moves and waste their time...My advice is to choose few basic exercises which have proven to produce results and stick with it.