Spirits work out exceptionally well together.
As do the Ents and the Giants. Same with Sphinx tribe.
I was not impressed with Carvers nor the Inox or Angel lines.
The Carnage line similarly was unimpressive, as it didn’t have enough synergy. The first creature is fantastic (Fallen Carnage) - which imo, should be the LAST creature in the line. That entire family works as a one-off addition to a lineup rather than a cohesive tribe you wish to put 6 of. It also shines when you can pick up both Life and Death magic from the Chaos perks.
The Fiend line has a similar fate to the Carnage line; they work as one-off additions to a team to bring a strong melee attacker, but you really wouldn’t desire 6 of them.
I think a better implementation for tribes would be similar to the Sphinx concept/traits; tribe bonuses get applied when you have 2+ creatures of the same tribe in your team and are in ADDITION to the standard creature traits (with some obvious reworking of existing traits). This would also allow for mixing of tribes to a certain extent with the lower-level bonuses. I also LOVE the tribe traits like Sphinx Ordainer, but I feel it’s not really taken advantage of because it requires another trait to work.
Conceptually, it would be something like this:
[size=18pt]Sphinx Tribe Bonus[/size]
Themes: stat gains, stat debuffs, action queue randomization
2: All of your creatures gain 5% stats for each Sphinx creature in your party
3: Enemies lose 5% stats for each Sphinx creature in your party
4: All of your creatures gain 5% additional spell damage for each Sphinx creature in your party
5: Your Sphinx creatures have a 3% chance of moving to the top of the action queue at the end of an enemy’s turn for each Sphinx creature in your party
6: At the end of each of your Sphinx’s turns, deal damage to a random enemy based on the level of your Sphinx and the difference of the target enemy’s position in the Action Queue.
So a full Sphinx team would now gain 30% stats and spell damage, enemies lose 30% stats, Sphinx creatures will randomly pop up to the top of the Action Queue, and at the end of their turn, they have an additional kill condition which to my knowledge, isn’t in the game (level based damage). The trade-off for having 6 Sphinx in your team, of course… is that you have 6 Sphinx in your team. You get a powerful ability based on the tribe, but it limits you severely on your composition/traits as well as locks you into Life spell gems only. If you need a method to dispelling debuffs, Life doesn’t offer you one.