We participated in a national night hike challenge a few years ago, and I gave all the leaders the badge as well (I wanted one for my campfire poncho 😁) as we had all done the night hike as well.
The same for the Water Day badge, as they ran a full afternoon for our and a neighbouring troop doing boating activities after our normal morning session.
I've given them the national scouting at home challenge badge in Covid, as they did a lot of the work organising challenges and dropping packs of materials and instructions to the house of each Cub, and ran a pretty full programme online, and ran 2 sessions per week when we were allowed meet in smaller groups - they had definitely put in the effort for that one!
We've given a few more fun badges (UK Scouts had a couple of Christmas themed ones that I got a full set of), and they took one the first year but not the second (I took both). But we "awarded" those on the basis of participation in the programme and all the f we'd had in our scouting year (which finishes at Christmas).
But all the leaders when I was there were former Scouts or Guides and had decent badge collections they had earned themselves.
I didn't give the annual progression badge or the adventure skills badges to leaders - we were teaching those things so well beyond level 1 🤣🤣. Although I was tempted to give 1 a firelighting badge and another a "I survived this year's camp" one for their skills in getting everything organised, lighting fires no matter what the weather and keeping everyone cheerful come what may. But I had to leave before the end of the year because of work so never got a chance to implement that one.