Maiar is a wallet powered by the Elrond blockchain that allows you to send payments to anyone just using your phone number. Basically making the whole crypto peer to peer transaction as easy as possible, no copying and pasting addresses, etc. It’s a payment system, kind of like Venmo, but on the blockchain.
Bondly is a completely separate project. It is described on the site as “A portable peer to peer exchange that enables trading across any chain, through any medium.” Essentially it does something similar to Maiar but isn’t just for peer to peer payments, it’s for trading any crypto asset, much more complex and on a bigger scale. They do have a token on the ETH blockchain that you can invest in (I have some). It’s not a wallet.
Uniswap is also completely different than Bondly. It’s a DEX (decentralized exchange) where peer to peer trading occurs only because people who have a token (like Bondly) offer to stake it in pools in return for profit, providing liquidity so others can get Bondly as well. This is the basic explanation, it can get much more complex. Uniswap is only for ETH-based (ERC-20) tokens.
Hope that answers your questions!