"Minimal 1", QRPp transmitter for 20m CW by OH1TV
I like to design and build minimal electronics. QRP and specially QRPp can be really minimalistic. It is often easier to make complex solutions than simple one's. In minimalistic design the product is improved by taking parts out.
https://oh1tv.fi/Minimal%201.htm

"The Bell Ringer" 20m CW Transceiver by AA1TJ
Here is a variation on the theme of the simple Pixie transceiver. In my version two 2N7000's form a push-pull PA with an output power in the neighborhood of 1.5W. This same transistor pair is used as a single-balanced product detector in a direct-conversion receiver.
http://web.archive.org/web/20101124023426/http://aa1tj.com/thebellringer.html

20/80m CW QSK QRP Transceiver by DL6ZB
This a 20/80m imaging CW QRP transceiver.
A transceiver technique "imaging" which was widely used by homebrewers during the 60's and 70's usually has a 9 MHz IF. A 5.0 to 5.5 MHz VFO results in 3.5/14 MHz input/output at the same time. The desired band has to be band filtered.
https://www.dl6zb.de/ZB-2/ZB-2.html

20m QRP CW 5W TRX by LY3H
I made already quite a few QSOs with the this transceiver, even with some JA stations.
http://ly3h.net/hello-world/

2N2/20 - A 20 Meter, Discrete Component CW Transceiver by K8IQY
The 2N2/20 is the latest incarnation of the rather long list of 2N2/XX designs. Departures from the all "2N2222 transistor dictate" provided an opportunity to use a variety of discrete semicondutors to enhance performance.
http://www.k8iqy.com/qrprigs/2n220/2N220Page.htm

A 20M QRP CW Transceiver built Manhattan Style by WØPWE
One of my favorite projects was this SST for 20 Meters. The SST was designed by Wayne Burdick, N6KR and described in the Spring 1997 issue of QRPp. The SST Kit is commercially available, but I though it would be fun to build one from scratch.
https://www.qsl.net/w0pwe/SST20.html

A CW QRP Tranceiver for 20m band by IK3OIL
The little QRP presented in this article may be built in a gradual manner, in fact it is divided in two main modules (plus VFO), you may also complete only a single part (RX or TX module).
https://digilander.libero.it/ik3oil/_private/rtx_eng.pdf
 

A Scratch-Build of N6KR and Wilderness Radio’s SST for 20M by AA7EE
I’ve been wanting to build an SST for a few years now. It’s a plucky little rig, with a lot of character. Designed by Wayne N6KR in the late 90’s, appearing as a full article in QRPp, and a kit sold by Wilderness Radio, it ignited the imaginations of a whole generation of builders for it’s combination of simplicity, performance, and willingness to accept modifications cheerfully.
https://aa7ee.wordpress.com/2016/09/09/a-scratch-build-of-n6kr-and-wilderness-radios-sst-for-20m/

A QRP SSB/CW Tranceiver for 14MHz by W7ZOI
Part 1: Exotic circuitry and hard-to-find components aren't necessary if you want to build excellent performance into a home-brew SSB/CW transceiver: Careful design is the key.
http://www.arrl.org/files/file/Technology/tis/info/pdf/8912018.pdf

A QRP SSB/CW Tranceiver for 14MHz by W7ZOI
Part 2: This moth, W7ZOI rounds out his description of a 1- or 10-W SSB/CW rig with details on its transmitter, TR switching and optional speech processor.
http://www.arrl.org/files/file/Technology/tis/info/pdf/9001028.pdf

AN7205 14Mhz TRX by LY3LP
http://sa555.blogspot.com/2010/03/an7205-14mhz-trx.html

Gnat 20m by LY3LP
http://sa555.blogspot.com/2009/07/gnat-20.html

Another GNAT 20 by LY3LP
https://sa555.blogspot.com/2009/07/another-gnat-20.html

Homebrew 20m CW Transceiver by 7N3WVM
Homebrew 20m CW Transceiver.
http://www.qsl.net/7n3wvm/xcvr-20m.html

Mijn Eerste QRP Rig "De Barefooter" door PA2OHH
Toen ik dit ontwerp vond, geloofde ik niet dat het mogelijk zou zijn om er QSO's mee te maken, omdat zijn eenvoud zo'n groot contrast was met de gebruikelijke amateur transceivers met hoog vermogen, superheterodyne ontvanger en andere complexe schakelingen.
http://www.qsl.net/pa2ohh/bafootnl.htm

MultiPig 20 Transceiver by W8PIG
The multiPIG is an Electronic Instrument that functions as an all band QRP Transceiver, a Signal Generator and a Frequency Counter.
http://www.fpqrp.org/pigg20/

The Multi-Pig Phased-Lock Loop Frequency Synthesizer by AA3SJ
The PLL is part of a larger project, the MP20 (multi-PIG) designed by Dieter Gentzow, W8DIZ. Details and construction lessons can be found at the MultiPIG web page.
http://www.qsl.net/aa3sj/Pages/MP20-PLL.html

Pocket sized 20m (30m) CW QRP transceiver by S56AL
I started to discover the 30m band by using an adapted version of my 80m single-board CW transceiver. The first impressions were quite encouraging, so I decided to build a portable transceiver for this interesting band.
https://www.s56al.si/ham_radio/tinka/tinka.html

QRP 14 MHz Transceiver of YU2TT by IZ3AYQ
YU2TT, Vojijslav, sent me the schemas of his transceiver, ad i am happy to publish his work. So, every one with some experience in electronics can build his own transceiver ! In same ways it is inspired by the Toucan of F6BQU, but it has its own changes.
http://iz3ayq.blogspot.com/2018/07/qrp-14-mhz-transceiver-of-yu2tt.html

Radio Ozon - Miniature 20m CW station by GØUPL
This project aims to build a complete miniature 20m handheld tranceiver into an Ozon mint tin. These mints are available at many newsagents here in the UK. The target is a complete station in a box, not just a transceiver.
http://www.hanssummers.com/ozon.html

The Wuther - 20m CW QRPp Transceiver by SP5DDJ
Just by the end of the year 2002 new QRP rig became alive. I called it "The Wuther". The concept of my smallest rig was taken from experience and some ideas presented in the Web by my distinguished colleagues - Wayne N6KR, David W0CH, Wayne NB6M and many others.
http://www.qsl.net/sp5ddj/wuther.htm

Un transceiver 14 Mhz simple de F6FEO
En juillet 2004, surfant sur le net, je découvrais un étrange montage de transceiver.
Appareil ultra-simple, décrit par un OM Indien Ashhar Farham, il s'agissait du BITX 20.
http://f6feo.homebuilder.free.fr/transceiver_simple_20m.html