Polaris in Other Media
For purposes of introduction, this post will simply highlight what exists, not share any particular thoughts about quality or that interpretation. CBR limits number of external images in a post to three, so I'm selecting the three I think should or must be highlighted instead of making multiple posts.
In general, Lorna didn't have much of a presence in other media until the mid/late 00s. The greatest activity for her is relatively new.
I'm not including Gifted on this list because it's already covered in the first post.
X-Men: The Animated Series
Lorna was in a few episodes of the 90s X-Men cartoon. At the time, she was mainly known for being a member of X-Factor and Havok's girlfriend, which were her roles in the story.
Wolverine and the X-Men
This cartoon came out in 2008 and was the first show to use and explore her relationship to her father and her family. The story of the season (and series) shows her on Genosha both in the present and in the future (after Genosha's destruction and the loss of her dad and family). One episode centers on her being wooed by Gambit.
X-Men Legends II: Rise of Apocalypse
Technically her first video game appearance. As explained by jmc247, Polaris was originally slated to be a meaningful character in the game due to her involvement in Genosha, but the role was passed to her sister Scarlet Witch. As a result, Lorna's role was reduced to being captured by Apocalypse and only briefly seen in the background.
Ultimate Marvel vs Capcom 3
I'm including this entry for completeness. Lorna is included in the background of art for Magneto's ending. Noteworthy is that during hype period, rumors circulated claiming Lorna would be playable alongside other characters like Apocalypse and Cyclops.
The Uncanny X-Men: Days of Future Past
A mobile game created as a tie-in with the live action film of the same name. Lorna was playable as an update, with her own distinct abilities and animations. Unfortunately, development ceased before release of Magneto (and I think Storm too), and the company that renamed itself as Gigataur shut down. The game can no longer be downloaded from app stores. But, it's significant for being her first playable appearance where she was uniquely worked on.
Lego Marvel Super Heroes
First playable appearance of Lorna, as an unlockable character. She was essentially a skin given Magneto's power set.
This completes the current list of notable other media appearances - again, aside from Gifted which was mentioned in the first post. To avoid having an excessively long list, I did not count trading cards/trading card games, brief use in audiobooks and similar content.