Searches for heavy quarks and other signatures with the ATLAS detector at the LHC

The Standard Model is very successful in describing nature but is thought to be an approximation to a more complete theory. Given that no clue has been found on the scale of new physics, signature-based search covering a wide range of final states and topologies is very important nowadays. Searches for fermionic top/bottom quark partners, referred to as vector-like quarks, are performed in various final states with leptons, jets, and missing transverse momentum ($p_T$). Searches in final states with a high $p_T$ jet or boson recoiling against large missing energy are quite powerful for detecting dark matter production. Long-lived, weakly-interacting particles predicted by various beyond-Standard-Model theories often lead to a signature with displaced decay vertices in ATLAS detector. This talk highlights recent ATLAS results on searches for vector-like quarks, dark matter, and long-lived particles in LHC Run 1 data at a center-of-mass energy of 8 TeV.