>>56950309Legit?:
Refer to pic related. You can Google if there is an updated list/image with possible DLC targets as this only takes into account Paldea targets. 6 star raids have better odds but several of them are more annoying to defeat solo. Either way, legit way is to scour the maps and manually check if they host your targets; if no targets you move your Switch's clock and reroll your dens to check again. Online method is to check raids online in the in-game board and try to join them if they host a juicy target. Both online and offline methods you still are at RNG's mercy to even get a single Herba drop.
Non legit?:
Join raids hosted in Twitch/Discord/Kick/Youtube whatever advertised as guaranteed 5-10 Herba drops. These are bots which used Raidcrawler to scour maps which auto-rerolled until they found raids which drop many guaranteed Herbas. After said raid completes the bot resets their game and re-hosts again for the public. You just need to win the raid with randos, you won't get into trouble for farming this way and if you don't want to further feel filthy then don't bother catching it at the end.
