The Hearthfire DLC adds a second Redguard female. There’s only one Altmer and one Redguard, both female, who can be married. There’s a persistent rumor that players can kill their spouses and remarry, but I suspect that’s a feature added by the Unofficial Skyrim Patch that PC players frequently download, or possibly a very early gameplay bug that was patched in subsequent updates, so don’t assume it will work for you. Skyrim allows one marriage and only one per Dragonborn, even if your spouse is killed - unless you use mods or console commands.
Others appear at random throughout the game. There’s a free one in a tent along the shoreline east of Dawnstar. It does not have to be an amulet purchased from Maramal, any amulet of Mara will do. You’ll also need to exhaust the dialog options with Maramal, the priest in the Temple of Mara in Riften, and be wearing an amulet of Mara in order to initiate a marriage proposal. Housecarls will be wiling to wed you as soon as they enter your service, mercenaries must be hired first, and other candidates have fetch quests or other requirements. You can marry anyone regardless of your Dragonborn’s race or gender, so long as you’ve fulfilled whatever conditions make them your friend. The Divines have blessed a total of 30 female marriage candidates and 37 male marriage candidates in The Elder Scrolls V: Skyrim and official expansions.
