Seconding Matrix, if you like the idea of chat rather than forum post format. You can also use the account in the Matrix network at large, quite a few techy hobby groups there, and of course one-to-one chat.

Endless Sky is wonderful, though the mobile version is a bit clunky (not even an “official” version afaik, but stitched on the ongoing-development FOSS game).

According to Wikipedia, the planetary boundaries -concept has been around since 2009, with some renaming and one variable change (“chemical pollution” to “novel entities”. The original Nature (feature) paper that I dug up doesn’t describe the methodology, but that it hasn’t faced major criticism so far would suggest it’s pretty valid for the kind of tool that it is.

I may be slightly envious.

Clay teapot.
Aged sheng pu’erh tea cake.
A good steep of a dan cong tea (so rare).
Live opera experience.
Vegetable patch.
Slushie.
My favourite pair of shoes (I did).
Alpaca/silk dress (yup).
Orgasm.

To be fair I always wanted more than one cat, just had to start with one.