for every 10? people,
1 ck
2 valk armor
1drobe
10 valk sheild
10 poo hats (beret is too good, no really!)
2 +5 dark bacilium
cards
enough bg badges for regular +4 gearset
a little ammo and edp
etc...
leave out high end stuff like elemental sword, its not necessary. AD barehand is enough, they'll have to work for the high end
tharas, raydrics, horn, noxious, alligator, marc, ED, etc. you should also probably increase monster rates for woe specific cards.
you can create custom "boxes" that have the items required. even class specific ones. define a maximum of 2 of each class or somesuch, a guild of 10 people claiming to all be champs/profs and thereby wanting drobes/CKs is nonsense.
I saw a guildpack that gave 1 mailbreaker[3] and swordbreaker[3] per 10 people, I drooled... theres always some bastard in a guild who likes this stuff
it helps to know about the classes, so you know what they really need
you can always check what other servers give to get ideas
if you give too much, soloists will hate and be jealous