"Vipormutant" Antenna by ON6MU
Versatile Inexpensive PORtable MUlti-band Tunable ANTenna. Well yes, one must have a name HI...It is nothing more then a base coil loaded antenna, but with a selector direct on the base to tune the antenna.
https://www.qsl.net/on6mu/schemas/vipormutant.htm

5 Band 1/4 wave Telescopic Antenna by EA5AVL
The 5-band antenna is simple and cheap to make, and has a performance that matches commercial antennas but at cost considerably lower.
https://rsars.files.wordpress.com/2013/01/5-band-telescopic-antenna-ea5avl-iss-1-3.pdf

A $20 HF Mobile Antenna by KM4IE
A few hours of fun with PVC and wire and you’ve got yourself a respectable road radiator!
http://www.arrl.org/files/file/Technology/tis/info/pdf/0004033.pdf

A $6.87 25 Foot 5 Band HF Vertical "The Wonder Stick" by N5VEG
A good working hf vertical for the price of a hamburger and fries!
The Wonder Stick is composed entirely of schedule 20 PVC pipe and a piece of copper-weld 12 gauge wire.
http://hamuniverse.com/n5vegvertical.html

A High Efficiency Extended Length Mobile Antenna by W5JGV
Much taller than the average Ham mobile antenna, this tree branch snapper tops out at 17 feet, 10 inches above the road. The antenna itself is 3.42 meters or 11 feet 2 inches long from the top of the mounting spring to the tip.
http://w5jgv.com/mobile_antenna/index.htm

A Linear Loaded Vertical Antenna for 40m and 80m by PA3HBB
As a lot of you will appreciate, to work good DX requires a low angle of radiation from the antenna. It is possible to achieve this low angle with a horizontal antenna, but only if sufficient height above ground can be achieved.
http://www.qsl.net/pa3hbb/ll.htm

An automatically tuned 7 to 30 MHz mobile antenna by XQ2FOD
For any ham who likes to travel, and who often travels by car, a mobile installation soon becomes a necessity. This is especially true when traveling on roads like the one depicted here!
https://ludens.cl/Electron/HFantenna/HFAntenna.html

Balcony Antenna by SMØVPO
Many amateurs are very restricted with the space they have available for HF antennas. I have documented a short antenna for the HF bands, but here is a simple method of mounting it, and a method of further reducing the length.
http://sm0vpo.altervista.org/antennas/balcant1.htm

Balcony Antenna Extension by SMØVPO
You may have already seen my HF Balcony Antenna which was designed solely for 14MHz, then a coil was added to cover all the lower HF bands (10, 7 and 3.5MHz).
http://sm0vpo.altervista.org/antennas/balcant2.htm

Build the PAC-12 Antenna a multi-band portable vertical designed by KA5DVS
Here’s an award-winning, easy-to-homebrew, multi-band portable vertical antenna designed by long-time antenna aficionado James Bennett, KA5DVS. He’s documented the design and construction plans for a portable antenna...
http://www.njqrp.club/pac-12/

Build This Novice Four-Band Vertical by WB1FSB
Putting your first amateur station together can be an expensive proposition. One way to cut costs is to keep the antenna simple. Here's how I shaved the price and provided four-band operation.
http://www.arrl.org/files/file/Technology/tis/info/pdf/7806016.pdf

Easy Multi Band Vertical Antenna for HF by MØAWS
Over the years I’ve built many multi band vertical HF antennas including multi-element quarter wave verticals like the DXCommander configuration, multiple end fed vertical dipoles all on the same pole and a host of other configurations.
https://m0aws.co.uk/?p=1998

Mobile/Portable HF Whip by G3YCC
I thought it may be of interest to describe simple to make HF whip antennas I have experimented with and used for a while.
http://www.zerobeat.net/g3ycc/yccwhip.htm
 

Multiband H-Pole by HB9MTN
After several attempts to build a multiband C-Pole I finally ended up with the Multiband H-Pole. C-Poles for different frequencies on one pole must be fed with separate feedlines over separate current baluns.
http://www.qsl.net/hb9mtn/hb9mtn_h-pole.html

Multiband Vertical Antenna Project by KV5R
The purpose of this project is to design a simple multiband vertical dipole antenna for 20 meters and above, with a tuner, that will provide gain and a circular pattern on the higher bands.
http://kv5r.com/ham-radio/a-big-vertical-antenna-project/

Short Antenna by SMØVPO
"QRP" operation often means operating in remote places where a decent full-sized antenna is not possible. I personally live in an appartment where I am unable to erect large antennas.
http://sm0vpo.altervista.org/antennas/short.htm

St. Louis Vertical by NFØR
The St. Louis Vertical (SLV) offers portable enthusiasts an easy-to-build, easy-to-use antenna which covers 10-40M via a balanced line tuner.
https://amqrp.org/st-louis-vertical/

The Offset Multiband Trapless Antenna (OMTA) by AL7KK
Once in a while an idea turns out to be so good that it can’t stay a secret. The offset multiband trapless antenna (OMTA) is so simple to build, so easy to employ and works so well, it fits that category.
http://www.arrl.org/files/file/Technology/tis/info/pdf/9510032.pdf