Just as it hadn’t been mentioned yet, arachidonic acid (SNS X-Gels, 6 caps/day) works very well for me in terms of strength, muscle fullness, and pump.
XPG Carnitine Gel (4 pumps pre-workout) provides a very big boost in workout endurance and power.
The combination may be synergistic, as supposedly carnitine can increase arachidonic acid incorporation into muscle.
It’s my favourite natural stack. Just be prepared for some serious DOMS.
Additionally, Prime XT did boost strength noticeably for me as well, interestingly this boost disappeared after cessation.