Many of the Linux commands that come to mind, some of which are not known, others are common, as follows:
Xargs or parallel: run some programs in parallel, commands have a lot of options
Sed and awk: well-known and very useful commands for working with text files, faster than Python and Ruby
M4: Simple macro-processing commands
Screen: Powerful terminal multiplexing and session persistence tools
Yes: Duplicate output string
Cal: a very nice calendar
ENV: Run a command that is useful in scripting
Look: Find English words beginning with a string
Cut and paste and join: Data manipulation commands
FMT: Formatting a piece of text
PR: Formatting a string of text or a larger file in page/column units
Fold: Make text line-wrapping
Column: Formatting text into columns or tables
Expand and Unexpand: Converting between tabs and spaces
NL: Add line number
SEQ: Print line number
BC: Calculators
Factor: The factor of the output integer, the mass factor of the factor output as an integer
NC: Network debugging and data transmission
DD: Move data between files and devices
File: Determine the type of a document
Stat: View file status
TAC: Output The file contents from the last line, and the cat output is the opposite
Shuf: Random selection of data on a file by row
Comm: Compare an ordered file by row
HD and BVI: Output or edit binary files
Strings: Viewing the contents of a binary file
TR: Character translation or manipulation of characters
Iconv or Uconv: converting encoded strings
Split and Csplit: Partitioning files
7z: Compressed file with high compression rate
LDD: Viewing dynamic library information
NM: View the symbol table in the destination file
AB: Web Server stress test Tool
Strace: Debug System call
MTR: Better route tracking tool for network debugging
CSSH: Visual concurrency Shell
Wireshark and Tshark: Packet Capture and network debugging
Host and dig: Finding DNS
Lsof: Viewing process file descriptors and socket information
Dstat: Useful System data Statistics tool
IOSTAT:CPU and disk usage statistics
Improved version of Htop:top
Last: Login History
W: currently logged in user
ID: View User/Group presentation information
SAR: View Historical system Statistics Tool
Iftop or Nethogs: View the network utilization of the socket or process
SS: View Statistics
DMESG: Boot or system error message
(Linux) Hdparm: Display or set disk parameters
(Linux) Lsb_release: View Linux system release information
(Linux) LSHW: viewing hardware information
Fortune, Ddate, and SL: It depends on whether you think a steam engine or a quote is useful.