If you miss Docker then suggesting You the Jails here would not help but if you miss typical GNU commands then you can install them like that:

    # pkg install coreutils

Now you have all GNU utulities with 'g' prefix:

    % pkg info -l coreutils | grep bin
        /usr/local/bin/g[
        /usr/local/bin/gb2sum
        /usr/local/bin/gbase32
        /usr/local/bin/gbase64
        /usr/local/bin/gbasename
        /usr/local/bin/gbasenc
        /usr/local/bin/gcat
        /usr/local/bin/gchcon
        /usr/local/bin/gchgrp
        /usr/local/bin/gchmod
        /usr/local/bin/gchown
        /usr/local/bin/gchroot
        /usr/local/bin/gcksum
        /usr/local/bin/gcomm
        /usr/local/bin/gcp
        /usr/local/bin/gcsplit
        /usr/local/bin/gcut
        /usr/local/bin/gdate
        /usr/local/bin/gdd
        /usr/local/bin/gdf
        /usr/local/bin/gdir
        /usr/local/bin/gdircolors
        /usr/local/bin/gdirname
        /usr/local/bin/gdu
        /usr/local/bin/gecho
        /usr/local/bin/genv
        /usr/local/bin/gexpand
        /usr/local/bin/gexpr
        /usr/local/bin/gfactor
        /usr/local/bin/gfalse
        /usr/local/bin/gfmt
        /usr/local/bin/gfold
        /usr/local/bin/ggroups
        /usr/local/bin/ghead
        /usr/local/bin/ghostid
        /usr/local/bin/gid
        /usr/local/bin/ginstall
        /usr/local/bin/gjoin
        /usr/local/bin/gkill
        /usr/local/bin/glink
        /usr/local/bin/gln
        /usr/local/bin/glogname
        /usr/local/bin/gls
        /usr/local/bin/gmd5sum
        /usr/local/bin/gmkdir
        /usr/local/bin/gmkfifo
        /usr/local/bin/gmknod
        /usr/local/bin/gmktemp
        /usr/local/bin/gmv
        /usr/local/bin/gnice
        /usr/local/bin/gnl
        /usr/local/bin/gnohup
        /usr/local/bin/gnproc
        /usr/local/bin/gnumfmt
        /usr/local/bin/gnustat
        /usr/local/bin/god
        /usr/local/bin/gpaste
        /usr/local/bin/gpathchk
        /usr/local/bin/gpinky
        /usr/local/bin/gpr
        /usr/local/bin/gprintenv
        /usr/local/bin/gprintf
        /usr/local/bin/gptx
        /usr/local/bin/gpwd
        /usr/local/bin/greadlink
        /usr/local/bin/grealpath
        /usr/local/bin/grm
        /usr/local/bin/grmdir
        /usr/local/bin/gruncon
        /usr/local/bin/gseq
        /usr/local/bin/gsha1sum
        /usr/local/bin/gsha224sum
        /usr/local/bin/gsha256sum
        /usr/local/bin/gsha384sum
        /usr/local/bin/gsha512sum
        /usr/local/bin/gshred
        /usr/local/bin/gshuf
        /usr/local/bin/gsleep
        /usr/local/bin/gsort
        /usr/local/bin/gsplit
        /usr/local/bin/gstdbuf
        /usr/local/bin/gstty
        /usr/local/bin/gsum
        /usr/local/bin/gsync
        /usr/local/bin/gtac
        /usr/local/bin/gtail
        /usr/local/bin/gtee
        /usr/local/bin/gtest
        /usr/local/bin/gtimeout
        /usr/local/bin/gtouch
        /usr/local/bin/gtr
        /usr/local/bin/gtrue
        /usr/local/bin/gtruncate
        /usr/local/bin/gtsort
        /usr/local/bin/gtty
        /usr/local/bin/guname
        /usr/local/bin/gunexpand
        /usr/local/bin/guniq
        /usr/local/bin/gunlink
        /usr/local/bin/guptime
        /usr/local/bin/gusers
        /usr/local/bin/gvdir
        /usr/local/bin/gwc
        /usr/local/bin/gwho
        /usr/local/bin/gwhoami
        /usr/local/bin/gyes