Usual Nickname, Unexpected Name: Bess/Beth/Betty

I originally started this post looking for new full forms for Beth, but it struck me that most could also work for Bess and/or Betty as well! All three are, of course, traditionally nicknames for Elizabeth, and generally considered "outdated", but Beth did have a bit of a revival in the 80s/90s thanks to Bethany.

Chances are, a lot of new babies today have a Bess, Betty, or Beth somewhere in their family line, and there are plenty of other names one could use to get those nicknames. :)

• Bestla (BEST-lah, Icelandic, Norse mythology)--from Old Norse, poss. "wife" or "tree bark"
• Bethan (BETH-an, Welsh)--diminutive of Elizabeth.
  Other forms include Besseta (BESS-et-ah, [archaic] Scottish), Betha (BETH-ah, [archaic] English), Betheline (BETH-eh-lyn, [archaic] English), Betsan (BET-san, Welsh), Bettan (BET-tan, Swedish), Bettina (bet-TEE-nah, German), Bettis (BET-tis, Swedish), Bettline (bet-LEE-neh, [archaic] German), Lisbet (LIS-bet, Scandinavian), and Lisbeth (LEEZ-bet, German).
• Bethania (beth-AHN-yah, [Biblical] Latin & Greek; bet-AHN-yah, Spanish)--form of Biblical Hebrew Bethany, poss. "house of dates".
  Other forms include Betania (bet-AHN-yah, Italian, Swedish, Spanish), Betânia (bet-AHN-yah, Portuguese), and Béthanie (bay-tah-NEE, French).
• Bethel (BETH-el, [Biblical] Hebrew)--"house of God"
• Bethia (BETH-ee-ah, [Biblical] Hebrew)--"daughter of God"
  [more commonly transliterated as Bithiah; sometimes used as an 'Anglicization' of Scottish Beathag, "life"]
• Bethsabée (bet-sah-BAY, French)--from Biblical Hebrew Bathsheba, prob. "daughter of oath".
  Other forms include Betsabá (bet-sab-AH, Portuguese), Betsabé (bet-sah-BAY, Spanish), Betsabea (bet-sah-BEH-ah, Italian), & Betsabeia (bet-sab-AY-ah, Portuguese). 
• Bethuela (bet-oo-EL-ah, Spanish; beth-WEL-ah, beth-yoo-EL-ah, [archaic] English)--from Biblical Hebrew, prob. "man of God".
  Another (very rare) form is Bethuelle (bet-oo-EL, French).
• Betlinde (bet-LEEN-deh, Germanic)--prob. "bright & soft" [possible source of the name Belinda]
• Betony (BET-ah-nee, English)
• Betrys (BET-ris, Welsh)--form of Beatrice
• Betsaida (bet-SYE-dah, Spanish)--from Biblical Hebrew Bethsaida, prob. "house of fishing"
• Bettina (bet-TEE-nah, Italian)--diminutive of Elisabetta or Benedetta.

Of course, many international forms & contractions of Elizabeth also work, especially for Betty:

• Arisbeth / Elibeth / Elisabet / Isabet (Spanish)
• Elisabet /Elsebeth / Elsebet (Scandinavian)
• Elisabete (Portuguese)
• Elisabetta (Italian)
• Elizabeta (Croatian, Slovenian)
• Elsabeth / Lilibeth (English)
• Erzsébet (Hungarian)
• Ilsebet / Ilsebeth (German, Danish)

And even more! Elizabeth has been used to form new combination names all over the western world (many overlapping between multiple languages), quite a few of which could also lead to Beth or Betty. Here's a small sampling:

• Annabeth / Annebet 
• Elínbet
• Embeth
• Evabeth
• Ingebeth
• Kajsabet
• Lillibeth / Lilibet / Lilybeth
• Marybeth / Maribeth / Maribet
• Rosabeth / Rosbet
• Sarabeth
• Ullabeth