Suggest away. I actually watch very few films, but I loved the glimpse into a certain side of Scottish culture provided by Trainspotting (Ye, I realize that not all Scottish people are vulgar, violent, drug-addicted criminals who are also funny as hell). I am mostly of Irish ancestry myself and am interested in the best films from Ireland as well.
For an Irish film you could try The Commitments; it is a comedy set in a poor part of Dublin but nowhere near as bleak as Trainspotting. For a more gentle comedy you could try The Waking of Ned Devine.
The charming Gregory's Girl - one of my favourites.
And, more darkly:
Calvary
The Magdalene Sisters
I think these last two are at least partly Irish funded if that counts.
The Song of the Sea - beautifully animated, intensely moving at the end, magical, beautiful soundtrack.
The Crying Game, My Name is Joe, The Wind that Shakes the Barley, Filth, Ratcatcher ...off top of my head.
I'm not going to suggest what I believe are the best examples at showing what Scottish culture might be. These are simply some that come to mind when I think of it on film because they accurately depict some aspect of Scottish life
Ratcatcher (1999) Lynne Ramsay https://www.imdb.com/title/tt0171685/
Gregory's Girl (1980) Bill Forsyth https://www.imdb.com/title/tt0082477/
That Sinking Feeling (1979) Bill Forsyth https://www.imdb.com/title/tt0080012/
Local Hero (1983) Bill Forsyth https://www.imdb.com/title/tt0085859/
I Know Where I'm Going (1945) Michael Powell https://www.imdb.com/title/tt0037800/
Sweet Sixteen (2002) Ken Loach https://www.imdb.com/title/tt0313670/
Neds (2010) Peter Mullan https://www.imdb.com/title/tt1560970/
Whisky Galore! (1949) Alexander Mackendrick https://www.imdb.com/title/tt4769214/
The Girl in the Picture (1985) Cary Parker https://www.imdb.com/title/tt0091116/
Ratcatcher (1999) Lynne Ramsay https://www.imdb.com/title/tt0171685/
Here you see and feel Glasgow and it's bleak, heavy, morbid, and the constant rain and grey people are never far from their default black mood and will either give you their last or stab you. And that's not an exaggeration. Depressing and tragic, but definitely honest. As far as I know this still hasn't had a theatrical release but can be found via Criterion. An aside: the director knows her stuff when it comes to film, but sadly she's also known for having a big mouth about the industry and so to some extent her reputation precedes her. More power to her!
Gregory's Girl (1980) Bill Forsyth https://www.imdb.com/title/tt0082477/
If Trainspotting presents a caricature (and that's the correct term) of a certain part of Edinburgh's population then here's the fluffy view on the West side of the coin. The biggest flaw is in some cases the acting, but also in how everyone is kind of soft and mollycoddled - teenagers from the posh side of town. But for the most part the humour survives intact and is typical of some parts of Scottish life/society.
That Sinking Feeling (1979) Bill Forsyth https://www.imdb.com/title/tt0080012/
It's perhaps unfair to suggest that this has the production values (but not the production style) of a school drama club who hire an Arriflex for the weekend, still, the fact remains that if an Ealing comedy was to be made in 1970s Glasgow although it wouldn't look like exactly like this it would be just as twee.
Note: there are two versions, one with the original (Glasgow) accent intact and another that was dubbed for the International market and uses more intelligible voices.
Local Hero (1983) Bill Forsyth https://www.imdb.com/title/tt0085859/
The last Forsyth film I'll suggest ('Comfort and Joy' wasn't for me) and my favourite. Only speaking from personal experience, then this is as realistic and authentic a picture of the West coast (and East coast) I've seen on film. There are communities of people exactly like this, with a day to day lifestyle containing the same quirks and eccentricities within an easy going dynamic. It has a Hollywood sheen, but it's real. Don't expect fireworks, just watch it for what it is and maybe with an Islay malt in your hand.
I Know Where I'm Going (1945) Michael Powell https://www.imdb.com/title/tt0037800/
Far more than the period piece it might resemble from the outside. In a way, perhaps the one true classic on this list. To this day much of island life remains as it's shown here. A huge nod from Bill Forsyth on his way to Local Hero.
Sweet Sixteen (2002) Ken Loach https://www.imdb.com/title/tt0313670/
By this point Ken Loach lost some of the edge he possessed at the peak of his powers, but his second best is still sharper and far more insightful here when it comes to the challenge of depicting Greenock and the familiar subject of disassociated youth/social deprivation.
I wouldn't go as far as the self important Internet critics who hurry to draw comparison with 'La Haine' - they only do so probably due to their frame of reference - and that of some of their readers - being relatively limited. Loach is one of those (rare) types who you should probably watch as much of their work as possible, because even the lesser pieces can shed light on the body of their work as a whole.
Neds (2010) Peter Mullan https://www.imdb.com/title/tt1560970/
Overreaches and heavy handed at points/fairly accurate in others. You should try not to meet a ned (chav) in real-life.
Whisky Galore! (1949) Alexander Mackendrick https://www.imdb.com/title/tt4769214/
Everyone should watch this and (hopefully!) smile.
The Girl in the Picture (1985) Cary Parker https://www.imdb.com/title/tt0091116/
Just 'cos.
Once is a 2007 Irish romantic musical drama film written and directed by John Carney. The film stars Glen Hansard and Markéta Irglová as two struggling musicians in Dublin, Ireland. Hansard and Irglová had previously performed music as the Swell Season, and composed and performed the film's original songs.
https://en.wikipedia.org/wiki/Once_(film)
(https://images-na.ssl-images-amazon.com/images/I/714DMRBu-sL._SL1089_.jpg)