Move tables and figures to the end of a section/chapter

One posibility is to us a stack-like system.

usepackage{etoolbox}
makeatletter
% Define a new stack by letting it to @empty
newcommandnewStack[1]{globallet#1@empty}
% add element to stack (top): addStack{<stack>}{<element>}
newcommandaddStack[2]{defele@ment{{#2} }xdef#1{ele@ment #1}}
% add element to stack (bottom) revaddStack{<stack>}{<element>}
newcommandrevaddStack[2]{defele@ment{{#2} }xdef#1{#1 ele@ment}}

% remove from stack
longdefpop@#1 #2@nil#3{defpopedStackElement{#1}%
  def#3{#2}}% remaining list
% stack name #1
newcommandpopStack[1]{letpopedStackElement@empty%
ifx #1@emptymessage{LaTeX warning: you are trying to remove an element from the empty stack noexpand#1 on input line theinputlineno}elseexpandafterpop@#1@nil#1fi}
% whipe stack
newcommandcleanStack[1]{globallet#1@empty}
makeatother

Depending on how complicate your floats are it is probably a good idea to put them in one file each and append them with something like

newcommand{printfloats}{begingroup%
  defdo##1{input{##1}}%
    dolistloop{myfloatsattheend}%
  endgroup}

which would require something like

newStack{myfloatsattheend}

[some text]

revaddstack{myfloatsattheend}{<floatsfilename1>}

[some text]

revaddstack{myfloatsattheend}{<floatsfilename2>}

and at the end of the section

printfloats
cleanStack{myfloatsattheend}