If do a veggie loaf. Basically, pick any ingredients from;
Breadcrumbs, fried onion, mushrooms, any lentils/beans, oats, nuts, spinach, courgette
Add herbs, egg or cheese to bind it and a spoonful of marmite.
Squash it into a tin or dish and bake.
Basically it's a bit like stuffing, but any combination will work.
(Blue cheese mushroom and spinach works well. As does cheddar, oats and nuts, Or lentils and courgette )
Just do any combination. And as long as it feels like a stiff cake mix it should hold together.