Three recent searches are presented for electroweak production of a vector-like top quark partner T of charge 2e/3 in association with a standard model top or bottom quark, using 2.3 fb^-1 of proton-proton collision data at
sqrt(s) = 13 TeV collected by the CMS experiment at the CERN
LHC. The searches, the first of their kind at this energy, are targeted to three decay modes of the T quark: tH, in a fully hadronic final state; tZ, in a dilepton final state; and bW, in a single lepton final state. All searches make use of algorithms to identify b quark jets and boosted W, H boson and top quark decays. Across a range of T quark masses from 700 – 1800 GeV, these searches place 95% C.L. upper limits on the production cross section times branching fraction of 0.37 –
0.93 pb (T -> tH), 0.11 – 2.0 pb (T -> bW), and 0.16 – 0.97 pb (T -> tZ).