Stumbled upon this thread and want to add some more that haven't been mentioned! I have a real athletic wear obsession (although still haven't tried Lululemon or Gymshark believe it or not!) I run, lift, do HIITs and bootcamp style stuff. Here are the brands I like/dislike...
Faves:
ECHT - I'm pretty obsessed with this brand. If you like butt scrunch leggings, these are phenomenal. Great fit (mostly high waisted styles), nice and thick/squatproof, and great compression. And they REALLY accentuate the booty. Like seriously. It's almost obscene....haha. I have a few of their non-scrunch styles too and love them just as much. The length is also perfect for me (5'4", 130 lbs)...no extra fabric in the ankles.
Firm Abs - This brand has some really unique and sexy designs. They have a great selection of cargo leggings if you like that style. And they accentuate the booty really nicely too. The material is a little thinner than I'd like, and so with lighter colors, it doesn't 100% hide cellulite, but I still love and wear them all the time.
OMKAGI (Amazon brand) - This is probably the highest rated scrunch butt legging on Amazon. And with good reason. They are super cheap, but great quality for the money. Honestly, I love them as much or maybe even more than my ECHT and FirmAbs leggings...they are simple in design, but damn they make my booty look better than any other legging I've tried. Not quite as crazy accentuated like ECHT. Just a perfect amount of scrunch really. And I wear mine constantly and they haven't worn out at all.
Noli Yoga - I love the styles and materials this brand puts out. I have their popular liquid leggings, and they are stunning and feel so nice. One of the few non-high waist styles I wear. And they do have some high waist styles too. Not amazing compression, so it's not perfect for all really intense workouts, but I still feel amazing in them. And I often pair with their bras and mesh flow tee.
Body Engineers/Engineered Life - Really fun designs. I have a pair that look like shorts, but have a netted part covering the legs and I love them. Good compression. Doesn't make the bum look as great as some that I have, but still good.
Some other brands I've tried, but are more hit or miss:
Marika (found on Amazon & Zulily) - some leggings I absolutely love and have great compression, while another has dug into my stomach in an uncomfortable way. But overall, I like the brand.
Jessica Simpson - I have a pair of leggings that are really cute design-wise, but dig funny in the stomach. I have a nice sports bra from her line though.
Alo Yoga - The designs and quality are great, and I so wanted to love the moto leggings, but they gave me camel toe like nothing else! And I've seen that as a frequent complaint about this brand.
Old Navy - these used to be my go to for just basic workout leggings. Haven't bought from them in a while though.
BSP Better Sports - have a pair that I really like. Nice design, comfortable. Offers 7/8 length.
Bali - bought one pair of leggings, and like some others, it digs weird in the belly.