it is really not clear what exactly would you need
standard TEdit has NumberOnly propery, AFAIR
TMaskEdit, mentioned above, can provide you with formatting like 012345.00
there is also TCalcEdit in Lazarus standard pallete, MISC tab, probably derived from RxLib
there is also another RxLib continuation, JediVCL, part of it was ported to Lazarus and is available in CCR, i has TJvCalcEdit and TJvValidateEdit
svn://svn.code.sf.net/p/lazarus-ccr/svn
https://wiki.delphi-jedi.org/wiki/JVCL_Help:TJvValidateEdithttps://wiki.delphi-jedi.org/wiki/JVCL_Help:TJvCalcEditJvValidateEdit has properties CheckChars, DecimalPlaces, DisplayPrefix, DisplaySuffix and others
JvCalcEdit has properties DecimalPlaces, DisplayFormat and others
KControls library has TKNumberEdit -
https://github.com/kryslt/KControls/