SharpSpell
- AJAX-enabled ASP.NET and Desktop spell checker component for .NET developers. [Commercial, trial version]
- http://www.tachyon-labs.com/sharpspell.aspx

Naxos Development
- Offers a collection of .NET user interface controls and components. [Commercial]
- http://www.naxosdev.com/

Dart Communications
- Offers a web-based HTML editor which enables users to create rich-text content in a browser as well as TCP and SNMP components.
- http://www.dart.com/

ASPBridge
- Component for including ASP code in ASP.NET pages.
- http://www.iprisma.com/aspbridge/

ZXValidator
- .NET component for credit card numbers validation. It currently supported credit card types: Visa, MasterCard, Amex, JCB, Diner's Club, Discover/Novus.
- http://zamov.online.fr/zxvalidator/

Real Components .NET
- .NET components for ASP.NET and Windows .NET applications includes IIS Manager, RSS Manager, Credit Card Validator, Web Header Manager. [Shareware]
- http://www.realcomponents.com/

Extreme Optimization
- Numerical components for .Net includes complex numbers, vectors and matrices (BLAS and LAPACK), numerical integration and differentiation, solving equations, curve fitting, special functions, statistics.
- http://www.extremeoptimization.com/

DotLucene
- A port of the Jakarta Lucene search engine. [Open source, Apache Software License]
- http://www.dotlucene.net/

NLinAlg
- A .NET class library for working with algebra structures such as matrices and vectors. [Open source, GPL]
- http://nlinalg.sourceforge.net/

fyiReporting Software's RDL Project
- A fully functional report and charting system based on Microsoft's Report Definition Language (RDL). [Open source, GPL]
- http://www.fyireporting.com

Lanap BotDetect
- .NET control to protect website from spambot (form robots) with asp.net captcha code image. ASP.NET security solution to prevent automated registrations.
- http://www.lanapsoft.com/

ASPPainter
- .NET component can be used to create new and edit existing images. Complete source code is available for developers. Free and commercial versions.
- http://dotnet.asppainter.com/

PortSight Secure Access for .NET
- Manages users and their access to WinForms and WebForms applications, Web Services and Web content. It features user roles, permissions, auditing, delegation and import from Active Directory.
- http://www.portsight.com/Products.aspx?AliasPath=Products/Secure%20Access/Secure%20Access&CultureAlias=en-US

PortSight Task Scheduler for .NET
- Immediate or planned execution from ASP.NET. It allows processing of long-running ASP.NET pages, running command line utilities or other server-side tasks without page time outs and under a privileged account.
- http://www.portsight.com/Products.aspx?AliasPath=Products/Task%20Scheduler/Task%20Scheduler&CultureAlias=en-US

EaseSoft Barcode
- .Net Windows Forms control and ASP.NET control for creating barcode images.
- http://www.easesoft.net

Industrial DOT NET, Inc
- Local IO assembly provides generic access to instrumentation data.
- http://industrialdotnet.com/

Quantum Whale
- Editor.NET component is an advanced code editor allowing integration of a highly flexible edit control in your .NET applications; Outbar.NET is a component pack allowing incorporate a side bar control into any .NET applications.
- http://www.qwhale.net

Xtras.Net
- An online reseller of third party .NET components.
- http://www.xtras.net/

Coalesys, Inc.
- Focusing on .ASP.NET User Interface controls.
- http://www.coalesys.com

decloak
- .Net components including: dual listbox with re-ordering, dependent listboxes, click click e-mail reports.
- http://www.decloak.com/Products/NET/

Subsembly
- .NET components based on e-Banking standards (FinTS, HBCI), e-Government standards (OSCI) and smart cards (PC/SC, CT-API).
- http://subsembly.com/

Olvio IT PlusSuite
- Include .Net controls, editor controls, layout manager, notification controls.
- http://www.olvio.com/WebModules/Products/PlusSuite/PlusSuite.aspx

BlackBytes Software & Consultancy, Ltd.
- Develops .NET components including: Security for .NET, Registry for .NET, DNS for .NET, NetworkTime for .NET, Whois for .NET, TimeZoneConverter for .NET, FTP for .NET.
- http://www.blackbytes-components.com

KineticaRT
- A collection of .Net components, including Windows .NET Forms сontrols, logic components, server components.
- http://www.kineticart.co.uk/Default.asp?page=Products/KineticaRT

Alvas.Net
- Offers components including Alvas.Suite, Alvas.Audio, Alvas.FileControls, Alvas.ShapeForms, Alvas.Controls, Alvas.Scriptor, and Alvas.Labels.
- http://www.alvas.net/

BlackBytes Registry for .NET
- Provides classes that manipulate the system registry.
- http://www.blackbytes-components.com/product.aspx?id=2&mt=1

Security for .NET
- Implement managed role-based security for .NET Framework. The Security for .NET enables you to manage Windows security.
- http://www.blackbytes-components.com/product.aspx?id=1&mt=1

Devshock .NET EventMonitor
- Component for notification of events in application. All information is queued and transfered in standard XML format. With this model the application thread is not blocked.
- http://www.devshock.com/products/tool/eventmonitor/

Devshock .NET ThreadPoolManager
- Offer an easy way to manage the .NET ThreadPool.
- http://www.devshock.com/products/tool/ThreadPoolManager/

WebCab Components
- .Net components for financial and mathematical applications.
- http://www.webcabcomponents.com/dotNET/

Parole Lite
- Generate pronounceable passwords. By 4ASPNET.
- http://www.4-asp.net/products/parolelite.aspx

Trace Listeners .NET
- A cyclic file trace listener. By ComponentSpace.
- http://www.componentspace.com/tracelisteners.aspx

Registry Toolkit .NET
- Extends the functionality of the Microsoft registry classes. By ComponentSpace.
- http://www.componentspace.com/registrytoolkit.aspx

CenterSpace NMath
- .Net components suite contains interfaces to BLAS and LAPACK, random number generators, anova, regression, probability distributions, sparse matrices, hypothesis tests and descriptive statistics.
- http://www.centerspace.net

etive.com
- Provides .NET components to use in both ASP.NET websites, and winform applications. Including dotEtiveFTP, dotEtiveSocket, dotEtiveTreeListView, etiveAspPack, etiveCreditCard, etiveDNS, etiveMessenger, etiveWHOIS.
- http://www.etive.com/

InRule .NET Rule Engine
- A rule engine that provides a framework for non-technical logic maintenance and deployment within server, web-based, and desktop applications.
- http://www.inrule.com

USPExpress Math Parser .NET
- Parse and evaluate scientific, engineering and mathematical expressions on-the-fly. BY Unisoft Plus, Ltd.
- http://www.unisoftplus.com/uspexpress/

SSDN: Simple Service Discovery for .NET
- An open source service discovery mechanism for .NET remoting. Also provides a simple naming and directory service.
- http://www.michaylov.com/spiro/ssdn/ssdn_overview.html

commandLine .NET
- Execute DOS/console commands from within .NET. Returns output, the DOS return code, and completion status. By AS-Pro Software.
- http://www.asprosoft.com/products_commandline.html