MTG - Lorwyn Eclipsed Collector Booster Box is a collection of 12 Collector Boosters, which are packs designed for collectors that contain premium, showcase, and foil cards, often with unique alternate art frames and special treatments
If you instead want to build a cube based around a particular theme or strategy, here are some ideas to get you started
Local places like comic book stores are fantastic for a quick, cash-in-hand sale, even if the price is a little lower than you might get online
The Tokens of Modern Horizons 3 Modern Horizons 3 delivers power and nostalgia, and the tokens, emblems, and helper cards from across its products will bolster your games with exciting art and a new ripple foil treatment!
Another one of us loves the power level of Branded, and another (me, specifically) has a great time running with a variety of decks centered around a control or alternative win condition playstyle
The Pokmon Company also often makes rare or exclusive cards that are naturally quite valuable to collectors
