Gabiramon
2022
It's a cool idea for a species pack. It was well implemented in a artistic concept with a new starship set and new art like every other species pack. The problem with this one is that the devs focused too much in bizarre gameplay mechanics that doesn't add to the roleplay and the strategic feeling of the game at all. They're just fun experiments with numbers and negative traits that don't add perspective to the game unless for "bigger numbers are cool" type of gameplay.
2019
Probably the best species pack alongside Plantoids, Lithoids adds a creative and innovative way to play the basic game. As a mineral-eating life form, your empire will grow slower, but will be much more durable and stable, like a mountain. And this is the expected gameplay from a species pack, it really adds a different way to play different from just an art pack and a couple of forgettable civics. Although this species pack lacks civics, it adds a interesting origin, unfortunately only for lithoids, but improves their base gameplay even further. Overall is a good species pack, better and original than the normal species packs.
2021
It's a great dlc, adds a entire new way to play the game as the Crisis. The main feature is to make your empire the main enemy of the Galaxy, basically a villain arc to destroy everyone while you built a new megastructure that destroys the galaxy itself. It really adds what it promises and does a great job at it, also adds great options for diplomacy.
2018
A good DLC overall. It adds the megacorporation government, extra megastructures, Ascension perks and some mechanics. The corporate government really gives the player more options for diplomacy and economy, basically becoming a must for every "pacific traders" style of run. It adds the ecumenopolis that adds a lot of economic boost on your empire, the option to play as a economy-centered empire and don't rely that much on war as before without this dlc.
2017
Basically this DLC is a must-buy for Stellaris. It adds basic elements of gameplay that improves the player's experience by various ways, since adding the Ascension paths that I can't imagine myself playing without them today, and adding the Dyson Sphere and Habitats that are huge improvements to the early and mid game. Basically this dlc adds a lot of flavor and elements for the game that you can't play without them once you get a taste. It should be part of the base game.
2016
2018
2020
2015