My first thought was to put it in to Altcoins
Which coin would you leave out or add to that?
Those you've mentioned are worth investing in as long as you believe they're good. You can clearly see they're not dying, so its up to you.
My personal choices are ETH, Swipe, Origin, Uniswap.
A mining rig is probably to expensive, also the powercosts in my country are not that great so not really a option I think.
Yeah this one is available for people who already bought every piece of equipment needed, but even for them it won't last forever - sooner or later bigger mining farms will take over the market completely.
There is no point investing in mining rig at the time we're discussing it.
Create my own T-shirt Company
Not a crypto related topic, but anyway here are my thoughts and observations:
This is a HIGHLY competitive market and I bet there are a lot of entrepreneurs that know how to do it better than you.
Tons of shitty products being produced monthly and I don't imply your will be same, but chances are if you decide to choose this path it will be a long-long investment, perhaps you'll have to invest in it even more to boost margin and profits at some point before you get any profits whatsoever.