Mirio might be shipped with his fellow "big three" member, the powerful and lovely Nejire Hado, but their relationship seems strictly platonic in the story of My Hero Academia. If a Mirio/Nejire romance isn't meant to be, then the cheerful, wholesome Mirio can pair up with girls his age from other anime series instead and find true love at last.
The elite sniper lady Yoko Littner is by far Gurren Lagann's Best Girl, and she is an invaluable ally and friend to protagonist Simon as well. At one point, Yoko and Kamina almost fell in love, only for Kamina to perish in battle against the Spiral King's forces. Yoko grieved, but in due time, she moved on, her optimistic spirits undiminished.
Yoko is ready for love once again, and Mirio Togata is a fine match for her. He can't pilot mechs, but he has the noble heart of a hero who will save one million people from All For One, the Spiral King, or any other threat, and with a great personality to match. Together, they will finally be able to find personal happiness.