[root@centos7 ~]# yum search telnet
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
* base: mirror.kakao.com
* epel: ftp.riken.jp
* extras: mirror.kakao.com
* updates: mirror.kakao.com
=================================================== N/S matched: telnet ===================================================
dcap-tunnel-telnet.x86_64 : Telnet tunnel for dCache
libguac-client-telnet.x86_64 : Telnet support for guacd
libtelnet.x86_64 : TELNET protocol parsing framework
libtelnet-devel.x86_64 : Header files for libtelnet
libtelnet-utils.x86_64 : TELNET utility programs from libtelnet
perl-Net-Telnet.noarch : Net-Telnet Perl module
telnet.x86_64 : The client program for the Telnet remote login protocol
telnet-server.x86_64 : The server program for the Telnet remote login protocol
procServ.x86_64 : Process server with telnet console and log access
putty.x86_64 : SSH, Telnet and Rlogin client
tn5250.i686 : 5250 Telnet protocol and Terminal
tn5250.x86_64 : 5250 Telnet protocol and Terminal

Name and summary matches only, use "search all" for everything.