I laminate the little ones using these Xyron laminating sheets, which come in different sizes. I don't laminate the big ones because I like to use glitter paper and it would be tough to get a nice look. You could laminate the big ones if you just used the boxes with no backing paper, or if the backing paper was not textured.
Finished product. These bookmarks, both large and small, are super quick and easy to make. They'd be nice little gifts or stocking stuffers or card tuck-ins for your favorite reader or tea nut.
As for the big, splashy ones...
There are tons of colors of glitter paper, with varying sizes of glitter and different textures. My favorite is the super fine grain glitter paper, but it's not as readily available as the others. Doesn't matter. Any of them will give a nice result.
Fox alert! See 'em?
You could cover the backs with pretty scrapbook paper, but I don't bother if I'm just making them for myself. Because both the box paper and the glitter paper are heavy, it helps to weigh them down with something heavy until the glue is dry to prevent curling. Make sure the glue is spread in a thin, even coating to prevent bumps and bubbles. Apart from the time it takes for the glue to dry, these can be made very quickly. I made half a dozen in less than an hour. Great for gifts.