The oldest was Scrapmetal and he came out around mid last year. Most of the other released Constructicons are shelfwarming at stores around me, particularly Hightower. Mixmaster and Scavenger (or is it Demolisher?) haven’t been release here that I recall but are available online. You haven’t really missed the boat yet. I don’t think there will be a box set as the RRP would be much higher than a Titan Class figure.