Some physical gill or plastron breathing Insects and Spiders:

Riolus cupreus (Flynn and Bush 2008)

Water boatman (Agraptocorixa eurtnome) (Matthews 2010)

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Aphellocheirus (Thorpe 1950)

Dytiscus marginalis (De Ruiter et al. 1951)

This file is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license. (credit: James Lindsey at Ecology of Commanster)

Cheirochela sp. (Thorpe 1950)

Hydrous piceus (De Ruiter et al. 1951)

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Corixa Geoffroyi (De Ruiter et al. 1951)

Arygyroneta aquatica (Shirtcliffe et al. 2006)

This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. (credit: Norbert Schuller Baupi)

Haemonia mutica (Flynn and Bush 2008)

Water striders (Aquarius paludum) (Goodwyn et al. 2008)

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Elmis maugei (Flynn and Bush 2008)

Pirata piraticus (Heckman 1983)

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Neoplea striola (Flynn and Bush 2008)

Pardosa amentata (Heckman 1983)

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Potamodytes tuberosus (Flynn and Bush 2008)

Notonectidae (family of backswimmers) (Flynn and Bush 2008)

This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. (credit: Luis Miguel Bugallo Sánchez)

Bathyphantes approximatus (Heckman 1983)

Hesperocorixa interrupta (Parsons 1970)

Tomocerus minor (Heckman 1983)

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Notonecta undulata (Parsons 1970)

Sigara striata (Heckman 1983)

This file is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license. (credit: James K. Lindsey of James Lindsey's Ecology of Commanster Site)

Ambrysus magniceps (Parsons 1970)

Gerris lacustris (Heckman 1983)

This file is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license. (credit: James K. Lindsey of James Lindsey's Ecology of Commanster Site)

Hydrotrephes balnearis (Thorpe 1950)

Aphelocheirus (Rahn and Paganelli 1968)

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Smithurides malmgreni (Heckman 1983)

...and many more!