Well, as far as I know...
Genya (Геня) - it's not used at all, imo.
Gena (with a hard G) is a nn for
Gennadi, and
Zhenya / Zhenia —
Evgeni.
Nazariy (Назарій) - it's a Ukrainian form, in Russian it should be Назарий, there is no letter 'i' in modern russian.
It's more like a 'church name', I mean, according to Wiki famous bearers are mostly bishops.
I think,
Nazar is a more conventional 'wearable' form.
But all in all
Nazar and
Nazariy are extremely rare and old-fashioned.
Anastasiy (Анастасий),
Iriney (Ириней) - same as
Nazariy.
Although my mother once knew someone, whose father was named
Anastas, I believe
Anastas was born in the 1940s-50s. (But honestly, I don't know where he was from).
Diminutives, that are not used as stand alone names:
Stas,
Fedya.
Tonya,
Lera.
Irredeemably dusty, 'your great grandmother' dusty:
Mariya,
Ustinya.
And I agree with ari on transcription issues.
I like
Kira,
Klara,
Ilia and
Lilia (these spellings).
Lilia is my long time favourite, actually. But it's an international name already...;)