I exported the published packages list that still rely on the camlp4 (I removed all pa_* packages as obsolete, and some of the packages that dropped camlp4 already, but not yet released, like coq or cocinelle):
- abt - https://github.com/ayberkt/abt/issues/6
- archimedes>=0.4.15 - https://github.com/Chris00/ocaml-cairo/issues/17
- batsh & >=0.0.6 - https://github.com/BYVoid/Batsh/issues/74
- bolt
- bookaml
- CamlGI
- config-file
- erm_xmpp - https://github.com/ermine/xmpp/issues/5
- extprot & >=1.3.0 - https://github.com/mfp/extprot/issues/33
- extunix - https://github.com/ygrek/extunix/issues/32
- froc - https://github.com/jaked/froc/issues/2
- gettext
- glsurf
- hardcaml-yosys - https://github.com/ujamjar/hardcaml-yosys/issues/5
- heptagon
- integration1d - https://github.com/Chris00/integration1d/issues/1
- iso-filesystem - https://github.com/jonludlam/ocaml-iso-filesystem/issues/3
- jitsu - DEPRECATED (and repository archived)
- joolog - https://github.com/hhugo/jsoolog/issues/1
- js-lz4
- json-static
- lambdoc - https://github.com/darioteixeira/lambdoc/issues/37
- lbfgs - https://github.com/Chris00/L-BFGS-ocaml/issues/7
- macaque - https://github.com/ocsigen/macaque/issues/40
- mascot - DEPRECATED (OCaml < 4.02)
- missinglib
- mldonkey>=3.1.3 https://github.com/ygrek/mldonkey/issues/36
- objsize - https://github.com/ygrek/objsize/issues/1
- ocamldot - https://github.com/zoggy/ocamldot/issues/4
- ocamldsort - DEPRECATED - use ocamldep
- ocamlscript - https://github.com/mjambon/ocamlscript/issues/6
- ocamlviz
- ocapic>=3.3 - https://github.com/bvaugon/ocapic/issues/5
- odb-server
- ospec>=0.3.0
- pfff - https://github.com/aryx/pfff/issues/4
- phox - https://github.com/craff/phox/issues/1
- planck<2.1.0 | >=2.2.0
- release>=1.1.1
- schoca
- sibylfs - https://github.com/sibylfs/sibylfs_src/issues/18
- spoc>=20170724 - https://github.com/mathiasbourgoin/SPOC/issues/51
- testrunner - https://github.com/zoggy/ocaml-testrunner/issues/1
- tftp - https://github.com/mor1/ocaml-tftp/issues/6
- ulex - it was ported to camlp5 already, but it is better to switch to sedlex, see Camlp5 and OCaml 4.08 for more information
- vrt - https://github.com/afiniate/vrt/issues/19
- wyrd>=1.4.6
So it makes sense to migrate the packages either to ppx, or to menhir/ocamllex/angstrom/whatever. Or, in the worst case - to camlp5. And if the project is dead - set the upper limit of the OCaml version to 4.08 in the opam file.