This excludes www/qt5-webengine and lang/python27 from the recursive search because they generate an infinite loop

/usr/ports/audio/csoundqt
/usr/ports/audio/faust-lv2
/usr/ports/audio/faustlive
/usr/ports/audio/guitarix-lv2
/usr/ports/audio/gxmms2
/usr/ports/audio/lxmusic
/usr/ports/audio/xmms2
/usr/ports/chinese/fcitx-sunpinyin
/usr/ports/chinese/sunpinyin
/usr/ports/databases/couchdb2
/usr/ports/databases/couchdb3
/usr/ports/databases/p5-AnyEvent-CouchDB
/usr/ports/databases/pypy-gdbm
/usr/ports/databases/pypy-sqlite3
/usr/ports/devel/containers
/usr/ports/devel/d-scanner
/usr/ports/devel/dcd-client
/usr/ports/devel/dcd-server
/usr/ports/devel/derelict-sdl2
/usr/ports/devel/derelict-util
/usr/ports/devel/dlib
/usr/ports/devel/dsymbol
/usr/ports/devel/dub
/usr/ports/devel/electron7
/usr/ports/devel/flang
/usr/ports/devel/flang-clang
/usr/ports/devel/gnatpython
/usr/ports/devel/godot2
/usr/ports/devel/godot2-tools
/usr/ports/devel/hgreviewboard
/usr/ports/devel/icontheme
/usr/ports/devel/inifiled
/usr/ports/devel/inilike
/usr/ports/devel/isfreedesktop
/usr/ports/devel/libclc
/usr/ports/devel/libddoc
/usr/ports/devel/libdparse
/usr/ports/devel/libhid
/usr/ports/devel/libosmo-abis
/usr/ports/devel/libosmocore
/usr/ports/devel/llvm60
/usr/ports/devel/llvm70
/usr/ports/devel/mir-core
/usr/ports/devel/msgpack-d
/usr/ports/devel/py-enum34
/usr/ports/devel/py-subversion
/usr/ports/devel/rbtools
/usr/ports/devel/stdx-allocator
/usr/ports/devel/subversion-lts
/usr/ports/devel/viewvc
/usr/ports/devel/viewvc-devel
/usr/ports/devel/xdgpaths
/usr/ports/editors/vscode
/usr/ports/games/0ad
/usr/ports/games/minilens
/usr/ports/games/opendungeons
/usr/ports/games/renpy
/usr/ports/games/stratagus
/usr/ports/games/tanks-of-freedom
/usr/ports/games/wargus
/usr/ports/games/wyrmgus
/usr/ports/games/wyrmsun
/usr/ports/graphics/cegui
/usr/ports/graphics/derelict-gl3
/usr/ports/lang/clover
/usr/ports/lang/dlang-tools
/usr/ports/lang/ldc
/usr/ports/lang/ponyc
/usr/ports/lang/pypy
/usr/ports/lang/pypy3
/usr/ports/lang/python2
/usr/ports/lang/silq
/usr/ports/lang/spidermonkey185
/usr/ports/lang/spidermonkey52
/usr/ports/lang/spidermonkey60
/usr/ports/lang/tolua++
/usr/ports/mail/mailman
/usr/ports/math/aspcud
/usr/ports/math/gringo
/usr/ports/math/libpgmath
/usr/ports/math/py-pyasp
/usr/ports/multimedia/ffmpeg2theora
/usr/ports/multimedia/gmimms
/usr/ports/multimedia/gxine
/usr/ports/multimedia/mimms
/usr/ports/net-mgmt/icingaweb2-module-idoreports
/usr/ports/net-mgmt/icingaweb2-module-pdfexport
/usr/ports/net-mgmt/icingaweb2-module-reporting
/usr/ports/net/libproxy-mozjs
/usr/ports/net/onedrive
/usr/ports/net/openggsn
/usr/ports/print/derelict-ft
/usr/ports/sysutils/bhyve-firmware
/usr/ports/sysutils/bvm
/usr/ports/sysutils/uefi-edk2-bhyve
/usr/ports/sysutils/uefi-edk2-bhyve-csm
/usr/ports/sysutils/uefi-edk2-bhyve-devel
/usr/ports/sysutils/usbhotkey
/usr/ports/textproc/kibana6
/usr/ports/textproc/kibana7
/usr/ports/www/aws
/usr/ports/www/aws-demos
/usr/ports/www/chromium
/usr/ports/www/moinmoin
/usr/ports/www/node10
/usr/ports/www/node12
/usr/ports/www/npm-node10
/usr/ports/www/npm-node12
/usr/ports/www/sahi
/usr/ports/www/trac-devel
/usr/ports/www/yarn-node10
/usr/ports/www/yarn-node12
/usr/ports/x11-toolkits/gtkd
/usr/ports/x11-toolkits/pypy-tkinter
/usr/ports/x11/tilix

Search script:
#!/bin/sh

find_old()
{
	echo "$2" "$1"
	rdeps="$(grep $(make -C $1 -V PKGNAME) INDEX-13 | cut -f 2 -d \|)"
	for p in $rdeps ; do
		# don't recurse on ourselves
		if [ "$p" != "$1" ] && [ -z "$(grep $p donestuff)" ]; then
			v=$2
			v=$((v + 1))
			find_old $p $v
#			echo $p >> donestuff
		fi
	done
	echo $1 >> donestuff
}

rm donestuff
for p in $* ; do
	find_old $p 0
done

Input list (so without lang/python27 and www/qt5-webengine):
/usr/ports/audio/xmms2
/usr/ports/chinese/sunpinyin
/usr/ports/devel/electron7
/usr/ports/devel/gnatpython
/usr/ports/devel/godot2
/usr/ports/devel/godot2-tools
/usr/ports/devel/libclc
/usr/ports/devel/libhid
/usr/ports/devel/libosmocore
/usr/ports/devel/llvm60
/usr/ports/devel/llvm70
/usr/ports/devel/py-enum34
/usr/ports/devel/rbtools
/usr/ports/devel/subversion-lts
/usr/ports/devel/viewvc
/usr/ports/games/0ad
/usr/ports/games/renpy
/usr/ports/lang/pypy
/usr/ports/lang/pypy3
/usr/ports/lang/python2
/usr/ports/lang/spidermonkey185
/usr/ports/lang/spidermonkey52
/usr/ports/lang/spidermonkey60
/usr/ports/lang/tolua++
/usr/ports/mail/mailman
/usr/ports/math/gringo
/usr/ports/multimedia/ffmpeg2theora
/usr/ports/multimedia/mimms
/usr/ports/sysutils/uefi-edk2-bhyve
/usr/ports/sysutils/uefi-edk2-bhyve-csm
/usr/ports/sysutils/uefi-edk2-bhyve-devel
/usr/ports/www/chromium
/usr/ports/www/moinmoin
/usr/ports/www/node10
/usr/ports/www/node12