This one retails for $39.99 ($34.99 with discount). Enercore CR11 is a 20,000mAh power bank with 67W charging support. It features 1×USB-C input, 1× USB-C and 1× USB-A output.

If you're looking for a budget-friendly two-port adapter, consider Plugable's 40W Dual USB-C Charger. At $60, it is pricer, but it gives you the ability to power up a couple of devices at the same ...

Why not just use the existing wallet adapters? To bootstrap a dApp, we always find ourself doing the same thing over and over again, such as: Notification when wallets are selected, connecting, ...