This is a fantastic series @Punchy_Gungus ! Even motivated me to get signed up with an account after finding these forums last week.
First off, note these comments are coming from an admirer of this type of work and not a professional. Feel free to toss any of this in the bin if none of it resonates with you as you obviously know what you’re doing.
Chicago Stars- The shield continues to recall the Chicago Fire, perhaps too closely. The secondary logo is phenomenal and a great call to the famous Sears Tower. Perhaps make it the lead logo, or perhaps adapt the existing shield to some combination of the two?
Denver Mountaineers- Not sure Mountaineers is quite hitting the spot. Very reminiscent of the Rockies color wise, and the logo looks like a mishmash of past Nuggets and Rockies logos. The gray and purple pull me more towards a royalty theme here than it does for the baseball team for some reason, so there seems to be some sort of disconnect there.
As others have mentioned, if you want to go a different route with the mascot, Altitude is a possibility, but that rubs me more as a basketball team name than football. It also sounds a tad too new-agey, and football has always been better served with more rugged, classic names. Having said that, I do think an atypical mascot would be a good fit. How about the Colorado Climb? I think that gives off a pretty cool team identity of a team that builds upon success over time. Also think that would give you some room for a classic double letter design, perhaps even with a climber pulling himself up as he digs his axe in the lip of the C (or climbing up the curve?), but you’d have a better idea of what would work.
Jacksonville Cyclones- Both color schemes look good, but I think the Black and Blue have a more distinct feel and better relates to the mascot. Although… the blue comes out a little glossy and gives me more a “perfect, crystal clear sea water” feel than it does the feeling of a crushing hurricane. This isn’t necessarily a bad thing though, as the current look is very crisp.
You’ve already kind of got this going on with the northern lights squad also being extremely colorful, but something unique could maybe be a Doppler Radar theme (maybe just as alternates)?
Ottawa Grey Jays- Just wanted to note here that I really enjoy this design even if it isn’t one that jumps out at you. There is something beautiful about the quiet, stoic look of the Jay here. The more I see the design the more it grows on me. I wouldn’t mess with this one much, if at all.
Indianapolis Checkers- As others have mentioned, the grey is too dark. The best-looking logo is the black and white logo which better represents the checkered flag. Uniforms are sharp.
Houston Voyagers- Great choice on the color change. Looks much, much better. I also really like the black and white logo here as well. Any thought on further implementing that? It brings a call back to the space race and the black and white televisions with which the world viewed the moon landing.
Minnesota Lumberjacks- My favorite design simply due to the gorgeous M with the negative space spruces. I do think the logo is a little busy though. Could the negative space at the top of the M (the diamond shape) be a simpler, more discrete reference to the northern star? I just feel like the winner here is that M design and the star design is pulling away from its glory. Your design there was so good, you may have had all the elements you were looking for without even realizing it!
For the uniforms, perhaps add some chevron on the legging pattern to represent the spruces in the uniform design as well? Or on the helmet?
Top 5 favorite designs so far-
1- Minnesota Lumberjacks
2- Lumiéres du Québec
3- Mexico City Stingrays
4- Las Vegas Venom
5- Ottawa Grey Jays
Overall feedback- There are a good number of the uniforms that utilize the same pattering for the helmet stripe, sleeving and leg. Maybe try changing it up on some of these, especially on the designs with a more unique pattering, like Vegas or Chicago. Repeating the pattern in several spots can have the opposite of the desired effect and instead mute the uniqueness since its everywhere we look.
Some of the weaker designs I feel (after Mountaineers) are the Baltimore Warriors and Seattle Shockwaves. They are still great (they all are!), but if you decide to revisit any I would put those at the head of the list.