I'm not sure how exactly it started, but months back I was wondering how certain logos might look if that city had all their teams with similar colours, so I decided to do a mashup of all the teams in the major 4 pro sports leagues. Meaning how might the Boston Celtics look with Bruins colours and vice-versa. For the most part the early criteria is that they need to have the same city name(EX-Toronto Blue Jays/Raptors/Leafs). So even if some might be in same city(like Oakland A's and Golden State Warriors) I didn't do those ones just to save some time. If people want me to do more, then let me know and I'll do more.
Ones like NY,LA,Chicago who have many teams, I might do later. Some I skipped because their primary logo is just too plain for this to really work(such as Indians and Pirates logo where the logo is basically just a letter). A fair amount I also didn't do if I felt the colour swap wasn't so noticeable and was nothing more than a slight difference in colour tone(EX-Washington teams red/blue). Some swaps I find look nice(like ones attached here) while others not so much(O's under Ravens colours, Bengals under Reds colours ect.), but I still did them just to see how they all look.
If there are other requests you would like for me to do or see some that are missing, feel free to post it here and I'll do my best to complete it. My next project might just be colour swapping current/past logos of a teams history for those who have had notable changes, such as Brewers,Stars among others.