Actually that's a great example, because using it wrong doesn't change its value.
Look at the commisar squad. Both of his infantry modifier abilities have no cost to use but generate value. Free but valuable.
Something can have no cost and still have worth.
. The free flares are, well... Free and provide recon without so much as an arming time. That's poor design frankly. Adding the need to deploy them would really round them out. This is legit the only commander I can think of that grants passive that require nothing from the player as I think about it.
You mean requiring some kind of input to gain the benefits of it, not just been a plain upgrade without cost right ?
If i have to make a list:
Units gaining abilities for free:
-IS/Rifles/Volks/Con building defenses or Conscripts been able to repair. Can't remember but Rifles used to have extended LoS on cover but it was really bugged and not working.
-Recent changes to Armor company with Elite vehicle crews.
-Hulldown. AT gun cammo. Dank Hunter Tanks cammo.
Changes to abilities:
-Old Thorough salvage (although not necessary a buff as it took longer).
Intel abilities:
-Radio Intercept and Forward "Intelligence/Or something like that". The bundle on the OW doctrine also gives their trucks the minimap passive ability.
So been strict, it's both OW intel abilities, Radio and Elite crews.