Suggestions for margbib
The following packages have something in common with the package margbib. The packages are ordered in decreasing similarity.
- cite: Improved citation handling in LaTeX
 - overcite: Compressed lists of superscript numerical citations
 - marginal: Extensions to \marginpar handling
 - bibentry: Full bibliography entries in the main text of a document
 - breakcites: Ensure that multiple citations may break at line end
 - mciteplus: Enhanced multiple citations
 - doipubmed: Special commands for use in bibliographies
 - lexitex: Footnote-style citations for law journals
 - mcite: Multiple items in a single citation
 - splitbib: Split and reorder your bibliography
 - hypernat: Allow hyperref and natbib to work together
 - xcite: Use citation keys from a different document
 - lastbib: Record the number of citations in a document
 - collref: Collect blocks of references into a single reference
 - citeright: Specify accurate natbib citations for diverse naming conventions
 - notoccite: Prevent trouble from citations in table of contents, etc.
 - drftcite: Print the bibliography in “draft” mode
 - marginfit: Improved margin notes
 - snotez: Typeset notes, in the margin
 - mnotes: Margin annotation for collaborative writing
 - mparhack: Work around a LaTeX bug in marginpars
 - marginfix: Patch \marginpar to avoid overfull margins
 - sidenotes: Typeset notes containing rich content, in the margin
 - flexipage: Flexible page geometry with marginalia
 - sidenotesplus: Place referenced notes, alerts, figures and tables into the document margin
 - xcpdftips: Natbib citations with PDF tooltips
 - chapterbib: Multiple bibliographies in a document
 - classics: Cite classic works
 - cite-bundle: Citation management bundle
 - citesidx: Produce a citation list for the bibliography
 - rangecite: Will turn a range of citations into something like [1..3]