Names lina/lena can be short for

[BiscuitLover09876]

So far I can think of:
LINA
Selina
Eileen
Milena

LENA
Helena
Elena
Magdalena

Eleni I mean

My great aunt was Lena. Short for Catherine. Where she lived the locals struggled to pronounce it, it came out as Catlena then shortened to Lena

Lena is a stand one name , I knew one.

Lena or Lina were probably the most popular girl's names in our very local area in Germany) about 16/17 years ago - also know a Magdalena that age but unshortened; the Lina and Lenas are all full names. DD has never been in a school class or out of school club without Lenas and Linas to confuse me with as when talking about friends/ acquaintances of hers I've only met briefly or never met I can't remember who's Lina or Lena

Definitely stand alone names, widely used.