What I like is the lack of logos, which men often prefer for a clean look.
1979 Gundam Mobile Suit Washed T-Shirt White L
The white tone here is exactly what you want from a basic tee—simple and pure.
Brand NEW Uniqlo Mobile Suit GUNDAM 45th Anniversary UT Graphic T-Shirt Size: M
You will find that the neckline sits nicely on men, not too loose or tight.
Gundam RX-78 T-Shirt Mens Small Crunchyroll Sunrise Anime Official Licensed
A nice touch here is the graphic print that uses only two contrasting colors.
RX-93-v2 Hi-ν Gundam Mecha Anime Graphic Tee – Mobile Suit Gundam
A nice touch is the black inner tag that doesn’t itch.