We offer an exploration of the spectrum of Effective Field Theories (EFT) which admit a unitary, causal, and local UV completion, through the use of Positivity bounds. We review some of the most important ideas of EFTs and Positivity. We explore positivity bounds for the EFT of a single weakly coupled massive vector field. When the mass is taken to zero, some of our bounds asymptote to the bounds obtained in the context of photons and massless scalars. We show that massive gravity violates positivity unless the cutoff is within 1 order of magnitude of the graviton's mass. We lastly study bounds in the context of effective field theories with massless particles. Focusing on massless particles coupled to gravity, we address the treatment of forward-limit divergences from loop discontinuities. While loop effects remain small, ensuring consistency in our approach leads to a significant impact on bounds, even at tree level.