to unlock metal the real way would be difficult, you have to kill all encounters in solteris to be able to buy them from a merchant and click them from the bazaar. The alt flagging which will bypass the required raids to use player made power sources have really 2 different tiers, teir 1 is all pure power sources but metal, and tier 2 includes all pure power sources. T1 encounters are any static zone raid tier bosses in SoF expansion, so spider in FM raid mob in loping planes, and raid mob in hills of shade. The blood moon raids are t1 also. Any other raid in SoF is counted as a t2 for power source flagging, all SoD encounters are t2 aswell. not sure on UF or hot but i know voa T1 does not counter for t1 or t2 power source flagging and all raids in rof and cotf do not count either for pure power source flagging.