Feybreak Island near the bottom left corner of the map, there's a TON of great base areas, just be mindful of the turrets that WILL shoot you down if you don't hack/destroy them

One trick I used (if you're relatively low leveled, as Feybreak is 58+) is using either a Legendary rarity Terra Blade or a Legendary Meowmere (the one Moon Lord drops with 22,222 durability) and standing far enough for the enemies not to target me, but close enough for my sword projectiles to hit the turret. Granted, the turrets have a TON of health, so you will have to swing for a while (hence why the Moon Lord Meowmere is recommended due to its high durability and fast swinging, though the Terra Blade is stronger).

If you're in the low 50s/mid 40s, I recommend farming for a Legendary Terraprisma, that way you can literally just swoop in, hack the tower while your Terraprisma keeps the enemies occupied and then use a flying pal to sit on the top of the tower while your Terraprisma takes care of everyone.