A wonderful initiation by @thp here. While we are it, shall we also look at the apps that lack proper descriptions too.

Is a separate thread necessary or shall we track them down here itself?

EDIT: I wanted to add few app to the wiki for which icons were missing. But can't login to wiki. I have an account already at garage.maemo though. Is this a common issue?
Anyways, apps whose icons are missing (from App Manager):
(Simple)Media Player Status Area Applet
aptly
camkeyd
d-feet
dbus-scripts-settings
healthcheck
joikuspot
less
longpress
macchanger
Maemo 5
morphquickpanaroma
Mplayer Movie Player (command-line only)
mussorgsky
Now Playing Notifications
pc-connectivity-manager
Petrovich
pool
powerlock
proximityd
pychecker
rootsh
Sharing plugin for fMMS
Simple Brightness Applet
speedy
tutorial-home-applet
Unzip add-on for the File Manager
usbcontrol
x11vnc


Apps whose icons probably need a small touch (from App Manager):
FM RDS Notify (Problem: nearly invisible on a black/dark background)
freecell4maemo (Problem: icon too small)
gFTP (GTK) (Problem: icon too small)
GiveMeFive (Problem: not clear on a black/dark background)
htop (Problem: icon can be made more informative)
maemo-periodic (Problem: icon is small and also not too informative)
maemo-recorder (Problem: icon can be made better)
Mirror (Problem: icon small)
PackageView (Problem: icon not clear on a black/dark background)
python2.5-py2deb (Problem: icon can be made more informative)
Recorder (Problem: icon can be made more informative)
Speech record and playback (Problem: icon is small)
symfonie (Problem: icon not even visible on a black/dark background)

App Menu:
CuteExplorer (Problem: icon can be more informative)
dbus-scripts-setting (Problem: icon can be more informative)
EightyOne (Problem: icon looks bit dull)
FM RDS Notify (Problem: icon not visible on a dark/black background)
Freecell4Maemo (Problem: icon looks bit pixelated)
gFTP (Problem: icon looks bit pixelated)
Maemo Periodic (Problem: icon not visible on a black/dark background)
MussOrgsky (Problem: icon looks bit pixelated)
myDicto (Speech record and playback) (Problem: icon is small)
Pendulum (Problem: icon not descriptive as name is)
Pool for maemo (Problem: icon missing)
Speedy (Problem: icon looks bit dull)
symfonie (Problem: icon missing)
USBControl (Problem: icon missing)
x11vnc (Problem: icon missing)

P.S. I will keep modifying this thread. So people who can edit the wiki, please keep an eye on this post.