Well, is there another way to spawn em? a mod-made way perhaps, other than straight up cheating?
Another way is to use transformation powder from Twilight forest mod.
What this does is turn vailla mobs into twilight forest mobs, or back again which is the part we're interested in.
So, what you want to do is explore the twilight forest and find some, it's dungeon loot style, so find a hedge maze for example, get the chests inside, find a well get chest etc. Look it up for more options
(it's all much easier with flight)
Once you've got transformation powder, you want to now find the mob to use it on, the one we're interested in is the skeleton druid. It's a skeleton with a hoe that shoots golden projectiles at you, they're found near a hut structure with a spawner of them inside.
Use the powder on them, murder them for soul shards or safari net them, or even just kill them (probably a waste of powder to do this)
Now as to why you want to go this pathway is their huts are much more frequent, and the spawner doesn't need to be set-up to make them spawn.