What social networks to choose for Parsing?

Question

API

I need to parse one or more social networks to fill the database (then it is planned to train the neural network). For which social network is it better to write a parser (it is planned to take what is freely available like a wall)? And for which it is better not to take it and why (such as limiting requests to 100 per minute or the absence of a normal api)?
I plan to write in python