The injection systems of heavy ion beam probe (HIBP) and beam emission spectroscopy (BES) plasma diagnostics must produce a beam with high enough intensity to obtain a reliable secondary signal. In particular, it can be achieved by improvements and optimization of the ion sources. Among a variety of them, the sources with solid-state thermo-ionic emitters have strong advantages in simplicity and very small (0,1 - 1 eV) initial energy dispersion. A high intensity alkali and alkali-earth ion sources of quasi-pierce geometry with solid-state thermo-ionic emitters of Li+, Na+, K+, Cs+ and Tl+ have been developed and investigated in IPP NSC "KIPT", Kharkov, Ukraine. In steady mode of operation the current densities up to 5.5 mA/cm2 are obtained with emitter capacity up to 9 mA ×hours. With not significant design modifications these ion sources are used on currently operating injectors of HIBP diagnostics on TJ-II stellarator (Spain), tokamaks: ?-10, ?U??N-3? (Russia) and ISTTOK (Portugal), and injector of BES diagnostic on ASDEX-U tokamak (Germany).