Abyssal Whip Special - Wraps/Stuns opponent prevents them from moving for 10 seconds. Hits up to 5. Drains 2/3 of special attack
Dragon Scimitar Special - Pretty much the same however it prevents opponent from using protection prayers for 10 seconds. Drains 1/2 of special attack.
Bow's - Rapid Option, fires 2 arrows at once with a decreased accuracy and max hit by 1/4. Eg. Max hit of 12 will go down to 9 along with low accuracy.
(I know theres recently been an update but its just a suggestion.)
God Prayers
Saradomin's Peace - Can't really explain this one, bit like a recoil ring but instead of dealing damage to your opponent it heals you. Drains 1 prayer per 3 seconds.
Zamorak's Wrath - Same as a recoil ring, however it applies for the amount of damage you do, not your opponent. Drains 1 prayer per 3 seconds
Guthix' Balance - Heals you by 2 and deals 2 damage to your opponent every 5 seconds. Drains 1 prayer per 3 seconds.
(you will only be able to use one of these prayers if you are wearing the corresponding cape/staff)
Edit: I also think that you should be able to see when prayer is being drained. Example-
Although I'm not totally sure on this one, might mess the game up a bit.
Let me know what you think