BT is the big one outside of the group. Well, Helvetic I think technically isn't Group either, but they are as good as Swiss subsidiary as far as I am concerned.
OS is leasing some ATRs from Braathens soon, but not yet.
There's a lot of wetleasing within the group. If we leave out LH separated AOC with Lufthansa branding, Air Dolomiti does a lot, although lately LH had been moving to "codeshare" model more instead of straight up ACMI.
I don't think there's currently any long haul ACMI, but 4Y did lease AY for a long time.