Rise or Fall has decent payout as well and might be easier if you need to solo on Elite.

You also might be able to do stratum 3 runs up to Basil, get recipes (Twisted anything, anything Pulsar, anything Blaster, etc.), sell them at the Auction House and buy the Orbs you need from the profit.

Are you capable of re-playing old missions from the story mode to gain the same rewards multiple times? Zero-Chill said to grind "The Sivereign Slime" and Tipiak mentioned "Rise or Fall". I thought once you got the rewards for beating that mission you couldn't get them again. Maybe I'm mistaken? Or do you mean that the drop rate for Orbs of Alchemy is higher on those missions? I'm currently looking for Advanced Orbs of Alchemy since I want to craft some 3-Stared Gear.

im surprised many people did not talk about this at all. a lot of people are talking about like vanaduke or the sovereign slime. Theres a 4 star mission called in cold blood. it has the most prize boxes in the whole game. if you play it on elite theres a high chance to get eternal orbs. the mission has 3 levels. they are all piercing themed. the first have wolvers. The second is based off of freeze and ice cubes. the third is mostly lizards. though there are some lumbers and puppies. This is a great place to get shining fire crystals as well. You get a span of 5-35 shinings. though the average is around 20-25. The whole thing can be done in around 7 minutes if you are good at dodging and have good rushing skills. I've gotten around 15 eternal orbs in total. you get 1 per like 5 runs usually. sometimes you get elite orbs. I had a friend who it was his first time playing and he got a elite orb right off the start. its a great level to farm and isn't hard at all. as long as you have a piercing weaopon and elemental and shadow, you'll be fine.

I disagree. Simply because it has more boxes doesn't mean it's better. It has a slim chance of red boxes compared to the granted 8 reds at the end of each boss-fight which always drop rarities it also doesn't give you tokens that you can use to get some gear to use or sell. One more downside is that it requires more preparation cause the monsters there are split between 4 types construct/beast/slime/gremlin where the boss levels only has like 2 and keep in mind that a new player who's grinding for orbs actually needs them to craft stuff to fight different monsters.

Orb drop rates are rare. Estimates from lancer knightz are around 0.5% drop rate. To my knowledge, I was the only one to separate out red and green boxes, which suggest that red boxes are 3x more likely to give orbs (0.9% and 0.3%). You gotta take into account that this data is based on a mere 41 observations. There is a much clearer trend of increased fire crystal drop (from ~19% in green to ~27% in red), so there likely is a difference.

However, these differences pale in comparison to optimizing level choice based on crowns.