The least expensive uniques that can go in health are the Numina Recov/Rech and the Miracle +Recov. Panacea +HP/End, because it is PvP, is more pricey. Those are my go to for health in that order.
In endurance, I go with the Performance Shifter Chance for + Endurance, which is not unique, meaning you can have more than one. Hello Physical Perfection.
If I need additional Endurance slots, I just use invention IO of appropriate level. up to 50+5. Not all builds need this. Like a blaster or stalker wont, but a solo defender will, or a high toggle scrapper, brute or tank might. Play it by ear.