theoremtypes.sty

\ProvidesPackage{theoremtypes}
\RequirePackage{amsthm}
\RequirePackage{thmtools}
\RequirePackage{xparse}
\RequirePackage{hyperref}

\newcommand{\NewTheoremType}[2]{%
    \newtheorem*{#1*}{#2}%
    \newtheorem{#1**}[theoremCounter]{#2}%
    \NewDocumentEnvironment{#1}{o}%
        {\IfValueTF{##1}
            {\begin{#1**}[##1]}% if argument is present
            {\begin{#1**}}% else
        \label{\thetheoremCounter}}%
        {\end{#1**}}%
}

\newtheorem{theoremCounter}%
{This is just a counter, which should not appear in the document}%
% change this to "chapter", "section", or similar depending on the desired enumeration
[section]

%Syntax: \NewTheoremType{Environment Name}{Header of Environment}

\NewTheoremType{corollary}{Corollary}
\NewTheoremType{lemma}{Lemma}
\NewTheoremType{proposition}{Proposition}
\NewTheoremType{remark}{Remark}
\NewTheoremType{theorem}{Theorem}

\theoremstyle{definition}
\NewTheoremType{definition}{Definition}