Using Soft Fascination
Putting your attention on something - direct attention / hard fascination - requires effort. Soft fascination requires little effort but also leaves mental space for reflection. More things can take more effort to do as an introvert and we need to figure out which of these it is to fully be able to recharge.
Anything to do with nature
Research from the Herriot-Watt University in Edinburgh did an experiment with 3 walking environments: an urban shopping district, a park, and a busy commercial zone. It showed that those who walked in the part hard lower levels of frustration and “engagement and arousal”, and higher meditative states.
How it translates to use: anything with plants, walks in nature, landscapes, water, wildlife, etc.
Extremes do not count
Though these may be relaxing they do not give us the restorative space we need. Watching TV (soaps), reading gossip columns, and nothing digital really.