The First League is kind of brokenly good right now, especially compared to the others. I've been super lucky and gotten it on each of my 2.2 games, and it's a massive boon. In my second game I colonized another size 25 planet near it and also turned it into an ecumenopolis. Ecumenopoleis get +20% to most (maybe all) resource production, on top of the insane alloy and consumer goods they can produce from jobs. I filled most of the building slots up with top tier research labs, and with science ships helping research, they produce around +1K of each type, each. That's like 35% of my entire empire's research production between them, and probably 70% of the consumer goods and alloy production.
I'm kind of expecting a nerf bat to head their way soon, hopefully with an unnerf bat for habitats.
On the subject of colonies, I wish there were more good colony events. Seems like the overwhelming majority are bad or are slanted toward bad outcomes. I lost 15 pops to the Horizon Signal event, and I just got the abandoned terraforming equipment event that killed an entire colony and turned it into a toxic world. That event in particular has almost no good outcomes, since it usually terraforms the planet into the wrong type for your species if it works, and if it doesn't work it can create monsters that kill your defense armies and take over, or it can apparently ruin the planet. And if you leave it alone or dismantle the equipment, the planet has a permanent -5-10% habitability and happiness value.
Then there's the time waster that is the psychoactive plants event that requires like 3 trips from a science ship to complete... the plague event, which at least used to give a unity building and maybe still does... the list goes on. The titanic life event also backfired on me in that game and made the titans mad, who proceeded to eat something like 15 armies before I retook control of the colony.