There are too many powders for the .243 to list all of them. First, you need to decide what bullet weight you prefer. Heavy bullets need slower burn powders; light bullets fast burning powders. Varget is one of the very best for all applications.
Standard 243...H4350 with Sierra 85gr and AA3100 for the 95gr Bal-Tip. Sako firearm BR-2 primers.
RL-19 in my 243AI Lapua brass BR-2 primers and 70gr Hammonds down a Douglas barrel 1-14. 1-9 Pac-Nor barrel 243AI 105gr Hornandy A-max over N-165.