In a tank that size you can keep a variety of agama (beardies, painted, rankins), various geckos (leo's, african fat tails, cresteds, gargoyles, various terrestrial geckos), uromastyx's etc. If you're set on that size you can split the viv in the middle and have 2 different setups (2x2ft is over the minimum recommendation for one leopard gecko)
You can keep a humid loving herp in a wooden viv but it must be well sealed, well varnished and have plenty of ventilation. The reason for this is that the wood can warp and your viv will be ruined, which is why most people just use a glass enclosure for humid setups.
Just find an animal you will enjoy keeping and are interested in, then look at their requirements to see if it is possible. Remember lots and lots of research