Bhuel a chairde,

What are some words that have different genders depending on the dialects?

A couple examples come to mind like: talamh, which is feminine in Munster and Connaght (with genitive talún and optionnally dative talúin) but is masculine in Ulster (with genitive talaimh); ainm, which is masculine in Connaght and Ulster (nom. an t-ainm, gen. an ainm) but is feminine in Munster (nom. an ainm, gen. na hainme).

On Wiktionary for example, sméar has a masculine declention (with gen. sméir) and a feminine one (with gen. sméire). Would that be a dialectal difference?

Who says talamh is feminine in Munster?

I think you mean that it is optionally feminine in the genitive only. So nominative is masculine talamh, and genitive is either tailimh (sic) or talún.

I compiled a list of words with different genders in Cork Irish at https://corkirish.wordpress.com/the-gender-of-nouns/

I was under the misconception that it was generally feminine in Munster, thank you for the clarification. I also found out that talaimh can also occur in Connaght and Munster, not just Ulster.