TeX & pTeX  の値とpreloaded(呼び込まれている)フォント一覧です
値は別として, Fontの方ですが \font\tenmin=min10 は原稿記述で直ぐに
\tenminで min10ptのfontが使えます.
\font\preloaded=min9 はmin9を呼び込んでいるが,原稿で使うには
例えば\font\ninemin=min9と原稿側の方で呼び出しコマンド名を記述(設定)して から使用する意味です.
(ご自分で検証するなら必ず原稿作業場所>ptex -ini ptex[Enter] でptex.logのopenで検証できます,
が同時に作成されたptex.fmtは必ず削除してください, TeX配布system側の*.fmt はさらに有益をpreloadedを持ったfmtです.)
This is pTeX, Version 3.14159265-p3.8.2 (utf8.sjis) (TeX Live 2019/W32TeX) (INITEX)  18 APR 2019 07:27
 restricted \write18 enabled.
 %&-line parsing enabled.
**ptex.ini
(c:/usr/local/share/texmf-dist/tex/ptex/ptex-base/ptex.ini
(c:/usr/local/share/texmf-dist/tex/ptex/ptex-base/ptex.tex
(c:/usr/local/share/texmf-dist/tex/plain/base/plain.tex
Preloading the plain format: codes, registers,
\maxdimen=\dimen10
\hideskip=\skip10
\centering=\skip11
\p@=\dimen11
\z@=\dimen12
\z@skip=\skip12
\voidb@x=\box10
 parameters,
\smallskipamount=\skip13
\medskipamount=\skip14
\bigskipamount=\skip15
\normalbaselineskip=\skip16
\normallineskip=\skip17
\normallineskiplimit=\dimen13
\jot=\dimen14
\interdisplaylinepenalty=\count23
\interfootnotelinepenalty=\count24
 fonts, more fonts,
\itfam=\fam4
\slfam=\fam5
\bffam=\fam6
\ttfam=\fam7

macros,
\strutbox=\box11
\mscount=\count25
\tabs=\box12
\tabsyet=\box13
\tabsdone=\box14
 math definitions,
\rootbox=\box15
\p@renwd=\dimen15
 output routines,
\headline=\toks10
\footline=\toks11
\footins=\insert254
\topins=\insert253
 hyphenation
(c:/usr/local/share/texmf-dist/tex/generic/hyphen/hyphen.tex))
\minfam=\fam8
\gtfam=\fam9
\tminfam=\fam10
\tgtfam=\fam11

(c:/usr/local/share/texmf-dist/tex/ptex/ptex-base/kinsoku.tex)) )
Beginning to dump on file ptex.fmt
 (preloaded format=ptex 2019.4.18)
2174 strings of total length 31165
5053 memory locations dumped; current usage is 128&4905
988 multiletter control sequences
\font\nullfont=nullfont
\font\tenrm=cmr10
\font\preloaded=cmr9
\font\preloaded=cmr8
\font\sevenrm=cmr7
\font\preloaded=cmr6
\font\fiverm=cmr5
\font\teni=cmmi10
\font\preloaded=cmmi9
\font\preloaded=cmmi8
\font\seveni=cmmi7
\font\preloaded=cmmi6
\font\fivei=cmmi5
\font\tensy=cmsy10
\font\preloaded=cmsy9
\font\preloaded=cmsy8
\font\sevensy=cmsy7
\font\preloaded=cmsy6
\font\fivesy=cmsy5
\font\tenex=cmex10
\font\preloaded=cmss10
\font\preloaded=cmssq8
\font\preloaded=cmssi10
\font\preloaded=cmssqi8
\font\tenbf=cmbx10
\font\preloaded=cmbx9
\font\preloaded=cmbx8
\font\sevenbf=cmbx7
\font\preloaded=cmbx6
\font\fivebf=cmbx5
\font\tentt=cmtt10
\font\preloaded=cmtt9
\font\preloaded=cmtt8
\font\preloaded=cmsltt10
\font\tensl=cmsl10
\font\preloaded=cmsl9
\font\preloaded=cmsl8
\font\tenit=cmti10
\font\preloaded=cmti9
\font\preloaded=cmti8
\font\preloaded=cmti7
\font\preloaded=cmu10
\font\preloaded=cmmib10
\font\preloaded=cmbsy10
\font\preloaded=cmcsc10
\font\preloaded=cmssbx10
\font\preloaded=cmdunh10
\font\preloaded=cmr7 at 14.51799pt
\font\preloaded=cmtt10 at 14.4pt
\font\preloaded=cmssbx10 at 14.4pt
\font\preloaded=manfnt
\font\tenmin=min10
\font\preloaded=min9
\font\preloaded=min8
\font\sevenmin=min7
\font\preloaded=min6
\font\fivemin=min5
\font\tengt=goth10
\font\preloaded=goth9
\font\preloaded=goth8
\font\sevengt=goth7
\font\preloaded=goth6
\font\fivegt=goth5
\font\tentmin=tmin10
\font\preloaded=tmin9
\font\preloaded=tmin8
\font\seventmin=tmin7
\font\preloaded=tmin6
\font\fivetmin=tmin5
\font\tentgt=tgoth10
\font\preloaded=tgoth9
\font\preloaded=tgoth8
\font\seventgt=tgoth7
\font\preloaded=tgoth6
\font\fivetgt=tgoth5
20343 words of font info for 74 preloaded fonts
14 hyphenation exceptions
Hyphenation trie of length 6075 has 181 ops out of 35111
  181 for language 0
No pages of output.