GiveawayNFT (ERC721)
Owner-only batch mint NFTs.
DonationTracker
Send ETH donations, track totals, owner can withdraw.
VotingSystem
Vote once for your favorite proposal.
SimpleEscrow
Buyer funds escrow, arbiter releases/refunds.
SubscriptionService
Subscribe for 1 month (very low cost).
TokenVesting
Claim vested ERC20 tokens.