I use OVH VPSs for simple projects as their service is cheap but reliable. Been using them for many years without a hitch. I've also got a dedicated server with SoYouStart which is a connected company to OVH.

I usually use Scaleway for VPSs or Dedicated for selfhosting, since their offerings usually have more cores than competing ones while having more or less the same amount of memory

Scaleway and Hetzner. Both are really cheap but still manage to give you a lot of power.

Heroku free dynos