I know the Oregon Ducks' logo is an O and an alternate logo for the Baltimore Orioles says "O's". I think that may be it for major American sports (not sure though), but there's probably more in smaller or international leagues.
Maybe
Cisco
Sharplink
On the front of their jerseys is a nationwide insurance logo, they have umbro jerseys.
victory
HBO
What logo is a black spider web
UNESCO
Lucasarts
american eagle
KLM