I'm looking for phrases which could be used in a similar way to "Best of a bad bunch"

The least (describer) of the group:

• The least expensive of an expensive group
• The least late of a late group
• The most developed of an underdeveloped group
• The youngest of an older group
• The lowest scorer of a low scoring group
• The least heinous in a band of thieves
• The fluffiest in a table of weak lattes
• The sun in a cloud of pale stars

They could be literal, or more fanciful/metaphoric/entertaining as in the latter examples. This may help you, if you want to or need to criticise - or at least call out the bad ones, without being critical or hurtful - which could work - as long it is done humourously but without actually poking fun.

It would, as commenters mention, help, if you told us what ‘the bunch’ is - since you don’t want to describe them as ‘bad’ - but ‘bad’ is the only description you have given us of them, thus far.

https://www.merriam-webster.com/dictionary/the%20least%20of