Most of my current charms are from the Glacor prodding!
There was a phase of 5m or so Slayer exp where I couldn't be bothered picking up charms before the imp came out.. But mainly a lot of things I've done didn't give good charms lol
For example, DG monsters give a lot of exp but no summoning exp, most of my post-99 strength exp came from DG, so to hazard a guess that's 80m str exp with practically no summon exp lol
Glacors are good exp per trip, but compared to the mage exp it's much less.. Around 140k summon exp (280k if doubled) compared to 570k magic exp. If I got 200m mage there, which I'm hesitant to do, I'd only get 17m exp (or 34m) worth of charms out of it
60m of my ranged exp came from Nex/QBD lol, Nex was alright for charms, but QBD was horrible