Zardnaar
Legend
I think this is one reason why home conversions from other editions works so well - the high level GM *already* has to tailor the material to his group, and doing a conversion to 5e you're not fooled into thinking the work has already been done for you.
I recommend using the second half of Paizo APs, quality varies (I bought a fire giants adventure that was terrible) but there is a lot of good stuff that easily converts to 5e 15-20; eg the second half of Rise of the Runelords and Shattered Star which I am using currently. There is also good OSR stuff, which can take slightly more work - eg JN3 Saga of the Giants, which is free in pdf and print-at-cost - http://www.basicfantasy.org/downloads.html
For those who find hordes of giants overwhelming in 5e, adding 50% to OSR/BX type D&D levels works well, so eg levels 8-12 becomes 12-18. With Pathfinder it's more like 25%, eg level 10 in PF works as level 13 in 5e.
I ran Monkey Isle. Those free Basicfantasy adventures are actually quite good and free.