With abstract games, there is generally no theme, or if there is one it isn't critical to the experience of the game.
Many abstract games also make great family games, which is why there is a wide selection available at Board Game Bandit. For some family-friendly abstract games check out Azul, Santorini, Calico, Tsuro, Patchwork (great for 2 players) and Sagrada.
Another great characteristic with abstract games is that many are card or tile placement games, allowing players to decide their own level of strategic play. Whatever your playing style, you will find some great abstract games with Board Game Bandit!