After paying off existing debt the next best thing once you have an emergency fund covered is stocks and maybe a little crypto if you're feel like future proofing yourself.
The yield on government bonds is really low at the moment and p2p loans can be finicky at best (I've lost more money than I've made from Mintos...).
Stocks have been giving great returns over the last few years and while there's almost certainly going to be a correction at some point its the only real place where you can get proper returns at the moment. You could invest in ETF (Exchange Traded Funds) which track certain buckets of funds like the S&P500 or invest in stocks individually.
Get yourself setup with a trading account - this varies by country and they have different fees etc but google should be able to sort you out here.