IC FM Transmitter

 https://www.electronicsforu.com/electronics-projects/simple-fm-transmitter

ua741 + Transistor = FM Transmiter with crystal voice:

http://electronics-diy.com/1km-fm-transmitter-with-ua741-opamp.php

And more:

http://blog.novaeletronica.com.br/micro-transmissor-de-fm/

https://www.te1.com.br/2014/05/super-transmissor-de-fm/

http://circuit-zone.com/index.php?cat=fm_transmitters

http://www.zpag.net/Electroniques/English/Radio/fm_3_transistor_circuits.html