The electronic spectra of new iron-based high-temperature superconductors and a number of other chemically similar compounds have been discussed and compared with the focus on iron chalcogenide K1-xFe2-ySe2, Se2 and isostructural pnictide BaFe2As2 (122). It has been shown that the Fermi surfaces in K1-xFe2-ySe2 are significantly different from those in pnictides. The LDA + DMFT and LDA' + DMFT calculations have demonstrated that the effect of electron correlations in K1-xFe2-ySe2 on the electronic structure is much stronger than that in the most studied 122 system. The electronic structure of several multiband superconductors similar in chemical composition to iron-based high-temperature superconductors, but having a relatively low Tc value (such as SrPt2As2, APt3P (A = Sr, Ca, La), and (Sr, Ca)Pd2As2), and the nonsuperconducting compound BaFe2Se3 has also been discussed. It has been shown that the electronic structure of these systems is significantly different from previously studied iron pnictides and chalcogenides. The Tc value in these systems can be understood within the simple Bardeen-Cooper-Schrieffer model.