Strong.app - Strenght training logger.

LogicLike - Improve logical thinking through engaging brain games

Ewolo - A simple, flexible mobile-friendly workout logger & tracker

Dualnback.works - Dual N-back is a specific brain training exercise, that's been shown by research - it might improve fluid intelligence.

Hevy - Simple workout logging, insightful analytics, and a growing community of gym athletes.

JobFlare - Brain games for job seekers