Which spells do winners most often learn?

In Dungeon Crawl Stone Soup — in the early game, the midgame, and the endgame — which spells are most often memorized by winners?

Solution 1:

The "Spell popularity" article on CrawlWiki, as well as <https://loom.shalott.org/learndb.html#good_spells>, contain some of the answers. This post is based mainly on those sources.

• In the early to mid-game: Mephitic Cloud. You can also use Passwall to escape monsters through 1-thickness walls.

• All game long: Blink, Apportation, Swiftness, Repel Missiles, Regeneration, Animate Skeleton, Summon Butterflies, and Flight.

• As soon as you can cast them reliably: Control Teleport and Haste.

See the aforementioned wiki article: it includes much more information. This includes information on direct-damage spells, plus a link to the raw endgame spell-popularity statistics.

_{This post is up-to-date for Crawl 0.14. Please edit the wiki article and this post, and add to them. If you'd like me to mark this answer as community-wiki, please comment and request it.}