A few random "Harpie" supports [4/4]

[Synchronized]

Castall, the Harpie Summoner
LV5/WIND
Spellcaster / Effect
If you control a "Harpie" monster OR if there are 4 or more "Harpie" cards in your Graveyard, you can Normal Summon this card without Tributing.  Face-up "Harpie" cards you control other than this card are unaffected by your opponent's Spell Cards.  Once, while this card is face-up on the field: You can Special Summon 1 Level 4 or lower "Harpie" monster from your Deck in face-up Defense Position.  You cannot Special Summon other monster(s) during the turn this effect is activated, except WIND monsters. 
2200/1600

(Yes, the name is a play on Castel, just for the humor of lore's sake.  I wanted to design something that would be able to tutor from the Deck more effectively, but I felt making it a Level 4 would be a bit too much because it would enable OTK combos with Harpie Channeler and such.  I intentionally wanted to make it playable, yet not abuseable.  The Spell protection effect is mainly intended to prevent you from field wipes and also get a bit more use out of Harpie's Hunting Ground, as well.)

Harpie's Pet Gryphon
LV6/WIND
Beast / Effect
Gains 300 ATK for each "Harpie" card in your Graveyard.  Cards and effects cannot be activated in response to the Normal or Special Summon of this card.  Your opponent must discard 1 card to the Graveyard as an additional cost to activate a Spell Card(s).  (This effect only applies for one copy of "Harpie's Pet Gryphon" regardless of how many "Harpie's Pet Gryphon" you control.) 
1800/300
 

(Designed based off the card 'Gryphon Wing'.  I actually included a bit of lore in that too, with the sense that Gryphon Wing counters Harpie's Feather Duster, and this card "counters" opponent's Spells.  Basically, I wanted to make another target for Channeler to bring out that can be a power card.  I made it weak because that boost can stack quick, but it makes up for it by being invincible upon summon. The final text of the effect is worded a bit poorly, but the intent was to make it clear that you can't have 3 of these on board and make your opponent have to discard 3 cards to use a Spell.)

Elegant Reflection
Quick-Play Spell Card
(1) Target 1 face-up "Harpie" card you control; it is unaffected by card effects until the end of this turn.  (2) You can banish this card (from your Graveyard): Target 1 face-up "Harpie" card you control; it is unaffected by card effects until the end of this turn.  You cannot activate the (2) effect of this card during the turn it is sent to the Graveyard.

(Literally Void Seer for Harpie's, but perhaps a little bit better.  I didn't want to make it a "Harpie" card just because of interactions it would have with the Blessings of Icarus card and stuff, but I think it's a useful asset that basically functions as a stronger Lance for the Deck.  And yes, it does work on the Field Spell.)

 

Harpie's Enchant - Blessings of Icarus
Normal Spell Card
Discard 1 "Harpie" card; draw 2 cards.  You cannot Special Summon during the turn this effect is activated, except for WIND monsters. You can only activate 1 "Blessings of Icarus" per turn.

(I had to be careful with this one because I know how good draw power can be, but I think I gave it enough restrictions to make it useful, but not abuseable with anything outside of Harpie's.  The speed would definitely help the Deck and eliminate dead draws while also fueling Hysteric Party and stuff like that.  I think it's definitely good, but not too much.)