These ETF/ETN you can put money into and get high monthly yields. But these are not going to grow your investment just give you good dividends. Sort of like buying an annuity. Where you are ok with putting the money in and not worrying if it shrinks. If you know for sure you can just leave the money there and hold the shares no matter what.
QYLD, RYLD pay about 12%
USOI pays about 30%
A safer one with growth and dividends is SCHD but only pays around 2.9%
There are other etfs you can look at some around 6-7% yields.